Unfortunately, the ventilation system sometimes does not work correctly. This is when it begins to blow from the ventilation back into the living quarters of the house. Brings air from the ventilation shaft with it unpleasant odors and you feel it right away. You should not postpone the solution of this problem indefinitely, because it will not be solved by itself. Let's see why ventilation works in the opposite direction.
Natural ventilation at home
What is this ventilation system? In fact, this is a complex of air ducts in a private house or a system of shafts in apartment building, in which there is one main riser, stretched from the basement to the roof. It is he who creates traction due to the temperature difference between indoors and outdoors. And the greater this difference, the stronger the hood works. Let's add the wind perpendicular pressure according to the type of cross sections. This is when the wind blows in a horizontal direction relative to the riser, and behind it it pulls air from the ventilation. That is, the suction of air from the premises occurs naturally, and not with the help of additional equipment such as a fan.
Of course, in such a system there must be an influx of air so that a vacuum does not form inside the house or the draft does not decrease. Therefore, vents are left in the foundation or holes are made in the floor of the first floor.
Causes of violation of air circulation
If the ventilation system is not working correctly, then there is a reason for that. There are many, but the main two are:
- There is no supply ventilation.
- The indoor temperature is lower than outside. This usually happens in the summer when it's hot.
But the main reason is still the lack of supply air flows. Usually in apartments, outlets to the ventilation shaft are made through the bathroom, toilet and kitchen. And the flow of air occurred through the windows (their leaks) and the front door. Today, when instead wooden windows plastic pipes are installed with complete sealing of joints and connections, the problem of inflow has become serious. Most often reverse thrust appears because of this. This problem is solved by installing inlet valves in window systems.
Other causes of traction disturbance and reverse flow include:
- malfunctions of the system itself;
- installation of fans instead of gratings;
- installation of a flow hood, which is connected to the ventilation duct;
- the absence of an umbrella on the roof or the destruction of the mouth of the channel.
Causes of ventilation failure
Causes of failure include a large number of factors. The main thing to understand is that when it blows from the ventilation system in the apartment, this is not the same thing if the same effect appeared in a private house. That is, malfunctions in two buildings can be different, because the violation of draft in them has different causes.
For example, in an apartment, most often this happens due to the installation of a fan or hood in the kitchen, which begins to press through its channel, and the air inside, moving to the riser with pressure, does not have time to go up with the whole mass. That is, it partially enters the adjacent channel of the toilet or bathroom. It is in these rooms that the opposite effect is formed. The same happens in the opposite direction if the kitchen fan is turned off and the toilet is turned on. This also happens with neighboring apartments located one above the other.
This suggests that it is impossible to mindlessly install additional exhaust devices without calculating their power. And the more powerful the fan, the stronger the reverse draft of the ventilation system in the apartment high-rise building.
For this reason, this cannot happen in a private house, because at the design stage today they are trying to distribute ventilation ducts to all rooms separately. That is, the kitchen has its own riser, the toilet and bathroom have their own. But sometimes there is another problem in the house. Most often, risers are combined into one or two common channels inside the attic, and then one or two pipes are led out through the roofing. And here horizontal sections appear in the ventilation system. The main task of the designer is to use as little of this type of duct as possible, and to minimize the angle of inclination of the horizontal sections (the decrease should be minimal). That is, the steeper this section, the better the upward movement of air.
And three more reasons:
- Lack of thermal insulation. Cold air in winter enters the air ducts, where it freezes, turning into ice. This usually occurs at the mouth of the canal. The consequences are a reduction in cross section.
- The absence of an umbrella (visor), which can lead to rain and reduce traction. This disrupts air circulation.
- The ventilation in the house is littered.
So, in order to remove reverse thrust, you must first understand why it appears.
Causes of reverse thrust
As mentioned above, reverse draft in ventilation appears for two main reasons:
- Full tightness of the premises.
- Installation of additional exhaust devices in the ventilation ducts.
All other reasons are secondary, some of which do not create reverse thrust, but simply the ventilation stops working. With ventilation in an apartment it is more difficult, because the system itself is a complex set of channels, often made of concrete. Branches depart from the riser for all apartments, through which the air from the premises must be removed to the street. And if a neighbor on the lower floor installs a powerful kitchen hood, then the reverse flow of air masses will be felt not only by him, but also by the neighbors from the floors closest to him.
In a private house, back draft occurs for other reasons, because the ventilation in the apartment is different from the ventilation system of a private house. This is where installing fans can solve the problem. But you just need to determine the installation location for different risers.
Self-determination of traction
- There are two ways:
- The simplest is to put your palm on the vent, and in case proper ventilation, You should feel the movement of the air flow.
- Attach a napkin or paper sheet to the grill. If the first holds on to the second, then the traction is good, there is no reverse effect.
Ventilation problems in multi-apartment buildings
Ventilation problems usually occur after years of home use.
- Its cross section becomes smaller due to the debris that has fallen inside, rodents and birds.
- Destruction of the walls of ventilation ducts due to condensate.
- The absence of a head is atmospheric precipitation that has got inside.
All this reduces traction, which means that humidity rises inside the apartments, and unpleasant odors will become the eternal companions of the rooms. What to do?
Solving the problem with a fan
Probably, many thought that the conversation was about installing fans in place of the ventilation grilles. No one forbids doing this, although it has already been described above what this can lead to.
We are talking about a fan that is installed in the system on the roof. It can be a mechanical deflector or a rotary turbine. Both devices are powered by a breath of wind, so in calm weather they are of no use. Although, as practice shows, it is the installation of these devices that dramatically increases traction and prevents reverse flow.
As for the fans on the ventilation grilles, it is worth first of all to calculate their power. It depends on the cross section of the ventilation ducts and on such an indicator as air exchange in the premises. For example, in the kitchen, this indicator should vary in the range of 12-20 m³ / h, depending on the type of stove and the number of burners.
To do this, you need to calculate the volume of the kitchen. For example, the area of the room is 3x4 m with a ceiling height of 3 m, the volume will be 36 m³. Now we multiply the resulting value by a factor of 12-20. At the minimum value, the fan capacity is 432, at the maximum 720 m³/h.
Preventive measures
What needs to be done to prevent backlash.
- Maintain the ventilation system in good condition.
- Do not install fans and extractors in ventilation ducts. Use a recirculation hood or take its outflow outside the room to the street: through a wall or window glass.
- Install baffles or rotary turbines at the end of the riser.
- Organize the flow of air into the premises by any means.
- Install interior doors, which will block the movement of air between rooms. Strong drafts are also causes of backflow.
- In winter, clean the ventilation system from snow and ice.
- Produce periodical
As you know, kitchen hoods are classic and recirculating. The first one takes air into the ventilation shaft or directly to the street.
Recirculation simply drives it through itself, retaining fat. It has filters in its design to clean the air from the smell.
The main questions and problems arise when installing and connecting exactly classic version. We will consider it in as much detail as possible.
First, let's briefly list the main mistakes that lie in wait for you along the way. Here are the ways to solve them and the most popular installation methods.
Mistakes when installing a kitchen hood
1 Blind connection of the duct to natural ventilation is the most common mistake.
Some, of course, leave a grate for the natural movement of air, but at the same time manage to block it anyway with the air duct itself. 
3 Outlet of the duct to the street through homemade hole in the wall. 
In most cases, this is prohibited by the rules. Further on the text will be given specific points.
Of course, you can lay a separate box along the facade straight to the roof. But is it worth it? Although in restaurants and cafes located on the first floors of high-rise buildings, this solution is widely used. 
By the way, the ban on air outlet through the wall does not apply to private houses, but only to high-rise buildings.
4 Complicated track geometry with many transitions and curves.
First of all, it will affect the noise. Although, of course, the turns themselves are not the greatest evil. And sometimes you can't do without them. 
It is the turns that go one after the other, without accelerating sections, that are dangerous.
5 Connecting a very powerful hood (for example, 1000 m3 / h) to a standard ventilation duct that can pass about 300 m3 / h.
Remember that a performance of 200-300 m3 / h is quite enough for quality removal all odors, with a minimum load on the ventilation of the house.
6 Installing the hood at the wrong height.
The installation height directly depends on what kind of stove you have - gas or induction cooking. 
Believe me, sometimes this design has to be disassembled.
8 Upper, not lower, arrangement of slots in a decorative grille in the same frame with an air duct.
Why this is a mistake, and when it is still possible to do so, is discussed further.
9 Lack of a separate outlet in the upper part of the wall under the hood.
As a result, connecting it at random, through carrying and extension cords. Keep in mind that it is not, after all, a portable appliance, such as a fan, heater, or mobile air conditioner. 
This means that the wiring under it must be done stationary and wisely.
10 Incorrect installation of the non-return valve.
It must be cut and installed in compliance with the appropriate angles and inclinations. Otherwise, it will work through time.
In general, the installation of the hood can be divided into two main stages. First, it is its connection to electricity. The second is the air duct device and everything connected with it.
Let's look at each of them separately.
Connecting the hood to electricity
This stage is the simplest. It is very good when you initially planned your kitchen, correctly laid the location of all sockets and electrical outlets. 
How not to make a bunch of elementary mistakes and keep all the distances, you can find in a separate article. 
If you do not have a free outlet for the hood, you will have to mount it. For this you will need the following materials:
In home wiring, use a cable of this particular brand (with the index Ls). 
- ordinary socket for current 16A with grounding contacts
The hood itself, unlike other kitchen appliances, is a low-power device. Accordingly, it is not at all necessary to pull a separate wiring under it directly from the switchboard.
What can not be said about the hob or dishwasher. 
It turns out that you can connect this unit from a common outlet group from the nearest distribution box. 
Pull a strobe or cable channel from the junction box to the place of the future outlet and mount the socket box. 
This outlet is located on top, almost under the ceiling, slightly above or to the side of the hood itself. The choice of a specific location will depend on the length of the cord and the requirement. minimum height installation of an exhaust unit above the stove. 
Often you have to cut a hole in the nearest kitchen cabinet for this case. 
Next, remove the insulation from the cable, mark the cores and connect them together in the junction box. 
All that remains is to correctly connect the outlet. 
The wiring for the kitchen unit is ready for you. Let's go to the duct.
Incorrect connection of the exhaust duct to the ventilation
The main problem during installation is to correctly connect the duct and at the same time not disturb the natural ventilation in the apartment.
Some of the craftsmen generally advise taking the whole thing out into the street, through the nearest wall. However, according to SNiP, this is prohibited. 
It clearly stipulates that such a hole cannot be placed closer than 8m from a neighboring window. Since this window is considered an outside air supply device.
Here, read the paragraphs of the set of rules SP54 and SP60. 
That is, drill a healthy hole in the wall, spend a lot of nerves and money, and the neighbor will complain about you, and you will be OBLIGED to fix it all.
How is the connection for most consumers? An ordinary corrugation is taken, put on the outlet, stretched and attached to the flange, which is screwed to the ventilation hole. 
That's all. Simple, cheap and wrong. What are the disadvantages of this method? First, the noise.
When air passes through such a ribbed corrugation, it makes extremely unpleasant sounds.
But most importantly, when your device is turned off and does not work, natural ventilation is forced to draw air from the apartment through the hood. Not only can your box be clogged, but in the summer there is sometimes no traction at all (due to the same temperature at home and outside). 
Moreover, in the air path, you actually put an oily grid, a motor, a turbine, etc. And yet, the air suction will not occur at the level of the ceiling, but at the level of the middle of the kitchen.
Although the sampling of all odors of waste products, just the same, it should be carried out from the maximum height.
It is quite clear that there will be no traction in this case. That is, you are your with my own hands deprive yourself of natural ventilation.
This threatens the occurrence of fungus, high humidity. In the off-season, your doors will simply begin to swell and close poorly. 
And there will also be a lack of oxygen and constantly feeling unwell. At the same time, someone gets into mysticism and begins to think that they have been damaged or an apartment with bad energy, but in fact, there it is - improper ventilation!
Initially, in Soviet times, when designing our multi-storey buildings, engineers expected that air would enter the apartment, among other things, due to leaks in wooden windows.
However, with the installation of plastic windows and sealed doors, we thereby blocked this channel. fresh air in the house. You will also close the ventilation and you will live like in a submarine.
To correct the situation in such cases, it is recommended to put the supply valve on a plastic window. 
Instead of clogging, you can do everything more intelligently. What kind alternatives used for this?
Air duct from the hood and grate with check valve
The first - instead of a corrugation, a plastic pipe is taken (for example, d-125mm), and through one or more elbows it is led into the hole of the ventilation duct. At the same time, a certain division is made in the hole itself under the ceiling.
An entry under the pipe is mounted on top, and a small rectangle is left through the grate with a valve below for natural inflow. 
Moreover, the grid should be exactly below, and not above. Otherwise, the air flow from the hood will blow up and lift, the so-called non-return valve. 
Although, of course, if you have a more advanced valve design - a circle or a rectangle with an offset axis, and not simple strips of polyethylene, or there is a solid partition, then you can safely put it as you want - from above, from the side, from below.
However, in fact, this whole design often does not work as intended. When you turn on the exhaust unit and create pressure, a small part of the dust still seeps through the cracks, micro-holes, after which it safely enters your kitchen on the dining table.
No check valves are 100% safe. The bulk of the air, of course, goes outside, but the gradual formation of dust inside the apartment is a fact. 
And when the hood is turned off due to a decrease in the diameter of the original hole, natural ventilation through narrow gratings will be much worse.
Everything can be done much better.
Proper connection of the duct to the ventilation system
For this you will need:
In the end, you should end up with something like this design. 
How does it all work? When the hood is turned off, the valve will open and warm air from the kitchen it will calmly go by gravity into the ventilation duct. As soon as you turn on the exhaust hood, the valve immediately closes automatically, blocking the air flow into the room. 
At the same time, all smells from the stove will calmly go outside. When turned off, the pressure in the box drops and the valve leans back on its own, connecting the ventilation shaft with the apartment.
Assembly instructions - all numbers and performance
How is it all put together in practice? For capacities up to 300 m3 / h (low speeds of most hoods), a d-125mm pipe is enough. On the device itself, the outlet can be large.
For example, for 650 m3 / h you will need a d-150mm pipe. However, such plastic pipes you are unlikely to find, and if you use the following standard size d-160mm, then it will turn out to be a huge and awkward design, spoiling the entire interior and kitchen design.
Moreover, you will have to hollow out the factory opening of the ventilation duct in the wall, expanding it. 
Therefore, in most cases, they choose optimal diameter in 125mm. And you don't need more.
Forced throughput of standard channels and shafts with dimensions of 100 * 150mm - 400 m3 / h. 
An air flow of more than 450 m3 / h will simply not fit in there (it was tested in practice), even if it is written on your hood - 1200 m3 / h!
Remember also that it is impossible to overestimate the diameter of the duct compared to the outlet pipe on the hood. Otherwise, the vibration and noise will be so strong that the structure will have to be glued again every month.
The connection of different diameters is done using special adapters. 
Let's start assembling. At the beginning, install the adapter on the hood and connect a vertical section to it. 
To improve its sound insulation, it makes sense to get confused and stick a heat-sound insulating material 5 mm thick on top. 
They also do not hurt to glue the decorative casing from the inside and the noisiest part - the adapter. It is there that the greatest turbulence is observed. 
All this is glued together with silicone, no superglues. There should be no cracks anywhere. 
We get to the trio. A valve is installed in it from the side of the room. 
Be aware that this is a gravity acting valve! It opens not due to the flow of air, but due to its own weight.
It has one half heavier than the other and at the same time it is set at a slight angle of 2 degrees. 
Preparing the opening of the ventilation shaft
Entry into the ventilation shaft itself before everyone installation work it is desirable to plaster and remove everything sharp corners. This will give the entrance maximum aerodynamic qualities. 
As a result, you should get approximately the same surface as in a standard round elbow at 90 degrees.
It is advised to add ceresit liquid (ceresit CT99) to the plaster solution. 
This hole will be exposed to grease and moisture. And ceresite contains components that prevent the formation of mold.
Under no circumstances should you use gypsum plaster. Its use in ventilation shafts is a direct way to the appearance of this very mold and fungi. 
Attach sections of a standard duct to the tee on both sides. From the side of the wall for 5-7 cm, wall it up in the ventilation duct. Ennoble the exit itself with a square frame. 
Why the check valve sometimes does not work and does not close
From the side of the kitchen, a check valve is mounted on the tee. In the factory version, it will be quite long. In this case, it is better to shorten it so that this "gun" does not stick out much. 
The valve is inserted inside a section of a standard duct d-125mm, and this duct is already put on and siliconized onto the tee.
If this whole design seemed too cumbersome to you, and the protruding pipe with a valve is not very aesthetic, you can do it a little differently. Make the air duct not a round pipe, but rectangular channels.
In this case, the above check valve is inserted in a straight section, as close as possible to the turn. 
A factory connection cannot be achieved here, so you have to collective farm. Buy a rectangular tee with round outlet on one side.
Next, this round timber is cut off and a check valve is glued in its place.
The valve is placed strictly at an angle (2 degrees). Otherwise, it will open every other time or not open at all.
Many have encountered this problem and easily solved it in this way.
The damper itself is also mounted with a vertical deviation. The upper turning point, based on the hourly dial, is at 13.00 (1 o'clock) and the lower one is at 17.00 (5 o'clock). This is if you have a flow direction from right to left. 
Otherwise, the circle is placed in the position of 11 o'clock - 7 o'clock.
For more reliable operation and stable opening of the damper, you can stick some kind of weighting agent (no more than 2 grams) on one of the sides. Glue it closer to the edge. 
By the way, do not throw away the round pipe cut off earlier. It is tightly inserted onto the valve from above, after which it is mounted on it decorative lattice diffuser.
What nuances can be with this method? If your hood is exactly above the entrance to the ventilation shaft, and the channel pipe goes straight, without any turns in the horizontal plane, then the valve installed in such a straight section does not work normally, at least at the 1st speed. 
You simply have nowhere to take the increased pressure to close it. Air in a straight line will fly through this "turn". You definitely need an angle.
valve cover and rotary mechanisms easy to clean and do not be afraid that they will become overgrown with grease. For this to happen, every day for several hours a day, you will have to fry on the stove and stew huge wild boars in your oven, no less. 
If you don’t want to see a protruding “hollow” under the ceiling at all, then as an option, you can install the tee in such a way that the middle knee rests against the wall, otherwise where the valve is, it would look to the side. In this case, the hole is also closed with a decorative cover.
Everything will look much prettier. However, due to the additional rotation, the natural ventilation performance will be slightly degraded. And the lattice will reduce it by another twenty percent.
In addition, the possibility of cleaning the channel with a hand or a vacuum cleaner will disappear. But many go for it consciously and even completely hide the entire structure in a wooden or plastic box. 
As they say, beauty requires sacrifice.
Why does the air from the kitchen get to the neighbors - is the hood to blame?
Despite all the advantages, there are many critics of such an exhaust connection system. They think that in this way you are grossly interfering with common system ventilation throughout the house.
For example, everything will be fine with you, but have you thought about the neighbors? Allegedly, due to such a connection of the hood to the ventilation, all smells from your kitchen will automatically penetrate into the apartments along the riser above. 
They started frying pies, and all the neighbors already know about it. However, all critics are mistaken, based on misconceptions about the ventilation system in apartment buildings.
They think that from the bottom to the top there is one common channel 110 * 150mm with "holes" for each apartment.
In fact, in 5-storey buildings, all channels are individual and you are unlikely to succeed in blowing out extraneous odors to your neighbors. In houses of 6 floors and above, already there is a system ventilation with air removal through satellite channels communicating with a common collection channel through one floor. 
This common channel has a cross-sectional area 6-8 times larger than individual shafts in apartments with dimensions of 110 * 150mm.
Schematically, such a ventilation system for a multi-storey building can be represented like this. 
Yes, in such buildings, if you turn on a maximum of several hoods SIMULTANEOUSLY, a reverse draft may appear. But this is an extremely rare case.
Look - the natural draft from the apartments at best ranges from 100 to 150 m3 / h. You have a nine-story house. The first seven floors are cut into a common channel with dimensions of 510 * 270mm, or even more. The final natural flow in it is about 1000 m3/h.
And here you, instead of the usual draft of 150, turn on your hood at 300 m3 / h. Do you think it is able to create a reverse draft in this case and start expelling air to the neighbors? 
To do this, it is necessary that all 6 floors do the same, moreover, at maximum speed.
That's when some one apartment is unlucky and its inhabitants will have to smell all the aromas of cooking neighbors. But this option is unlikely. 
Despite all this, sometimes the air from your kitchen actually gets into other apartments in the house. Or vice versa, you perfectly feel that the neighbors are frying for lunch today. Why is this happening and where to look for the cause?
This happens due to several circumstances. For which, read more in detail under the spoiler.
Why does the smell from your apartment penetrate to the neighbors
Illegal installation of the hood
However, if your house was originally designed only for a natural draft hood, and you got harmful neighbors, then any installation of powerful devices with mechanical forced circulation may turn out to be illegal. 
Neighbors can refer to the "Decree of the Government of Moscow." There is such a double point 3.4 "On the approval of standards for the operation of the housing stock."
You can turn it in any direction. Surely there are similar regulations in other regions. There is also an article 3.14.13.
So be careful with installation. exhaust hoods over the slabs.
Although the same rules recommend installing check valves on all ventilation grilles, in all apartments. That is, as it were, it is said that it is not forbidden for you to install a hood, but for everyone else you need to take care of yourself just in case.
But here the question is how lucky anyone will be with their neighbors.
In accordance with existing standards, any residential premises must be equipped without fail, which is designed to eliminate polluted air from not living rooms(toilet, bathroom, kitchen). In the event of a malfunction, the glass on the windows begins to fog up, condensate flows down the walls, the corners become damp, and mold forms in the rooms; if the ventilation system is working properly, such troubles are invisible. If the house is Small child, then the consequences of poor-quality air exchange can cause the baby to develop bronchial asthma or other respiratory diseases.
Scheme of the forced ventilation device in high-rise building
To check the performance of the ventilation system, you need to take a small piece of soft paper (about 10x10 cm), open a window in the room, and then bring a piece of paper to ventilation grille. In the event that the leaf sways, the ventilation works well. In turn, if the sheet is not attracted, this is an indicator of poor-quality operation of the ventilation system.
Ventilation problems in apartment buildings, especially on the upper floors, are quite common. The reason for the problems lies in the fact that in order to ensure normal circulation in the apartment, the air must pass through the ventilation duct at least 2 meters vertically. On the top floor, this condition is problematic, since the attic space acts as an obstacle. You can bring ventilation to the street using three different methods.
- The first - ventilation ducts, in the form of a pipe head, directly go to the roof. Houses were built in this way until the beginning of the 20th century, but the increased number of storeys of buildings gradually pushed this method aside.
- With the second method, ventilation, upon reaching the attic, was covered with horizontal sealed boxes connected to a shaft that went out over the roof.
- With the third method, the most modern, ventilation first enters the attic, which plays the role of an intermediate ventilation chamber. After that, the air enters the outside, passing through one common ventilation shaft.
We will not consider the first option, since it is not currently used - we will focus on the second and third methods.
In the second option, the following happens: air from all floors rises up through the channels, to the level of the attic, falling into a horizontal connected box, equipped in the attic room. During this, the air flow hits the cover of the horizontal ventilation duct. The air flow is slightly deviated towards the ventilation shaft, but if the internal section of the horizontal attic box is insufficient, a section appears in the box high blood pressure, due to which the air seeks an outlet to the outside through any nearby opening, for example, a ventilation shaft and an upper floor duct.
In the event that the section of the box is sufficient, but the cover is mounted very low, then the same process occurs - reverse thrust - the air flow does not have time to deviate towards the ventilation shaft, which entails a blow. The ventilation of the upper floor is “pressed through” by the reflected air flow, which is why odors from the lower floors fall into this particular room. To get rid of this, you can resort to two methods - global and local.
The global method involves an increase in the cross section of the attic horizontal junction box by changing its height by about 2-3 times, followed by the installation of some devices inside the box, called "cuts". Keep in mind that all these works must be carried out by experienced professionals. In addition, remember that it is not recommended to increase the cross section of the box in cases where ventilation shaft on the reverse side are attached exactly the same boxes.
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The local method involves separating the channels of the upper floor from the general air flow, followed by introduction into the ventilation shaft over the duct. You will need to carry out careful warming these individual channels in order to avoid disturbing the temperature and humidity regime of the attic.
According to the third option, ventilation works in almost all modern high-rise buildings. In most cases, ventilation on the upper floors in such houses is not accompanied by a reverse draft, but a weakened one. Air, in such cases, when it enters the channel, passes only about 30 cm vertically, after which it dissipates without having time to gain speed and strength. As a result, ventilation does not disappear, but air exchange on the upper floors is noticeably reduced. With open attic intersection and entrance doors, a strong draft can occur, due to which the draft on the upper floors becomes worse.
To eliminate this problem, it is necessary to increase the individual channels of the upper floor, the diameter of which is usually 140 mm. Pipes of the same diameter are put on these holes, and the joints are carefully covered with alabaster. The pipes are brought out to a height of 1 meter and slightly inclined towards the common shaft in such a way that the air flow that rises from below and passes next to the removed pipes draws air flows from the channels of the upper floor.
In apartment buildings, each apartment is equipped with a supply and exhaust ventilation system. As a rule, the ventilation scheme is as follows: there are exhaust openings in bathrooms, kitchens and bathrooms, and fresh air is supplied by ventilation of the premises.
Natural supply and exhaust ventilation of a residential building
High-quality work of supply and exhaust ventilation is able to fully provide a microclimate suitable for a person in the room. If unpleasant odors regularly appear in the room, and the windows fog up, this is a good reason to check the ventilation work. If the test showed poor system performance, then it is likely that the ventilation shaft is clogged.
Scheme of the device of natural supply and exhaust ventilation in an apartment building How to make the ventilation work in the apartment with your own hands
How to clean the ventilation in the apartment
If you decide to clean the ventilation, then keep in mind that the tenants apartment buildings do not have the right to exercise self-assembly engineering communications used by other people. Cleaning or repair of the ventilation shaft must be carried out only by specialists from the relevant organizations. If the ventilation and air conditioning of your home is not working, the only thing you can do is to remove the grate from the vent and remove the debris in it with a vacuum cleaner (or by hand).
In some cases it happens that exhaust system is in good condition, but unpleasant odors and misted windows still make themselves felt. This can often be observed in apartments where plastic windows are installed. In this case, there are two ways to solve the problem: regular ventilation of the rooms or installation of additional supply valves.
Drawing and installation diagram of the ventilation valve on the window Supply valves are usually installed in openings behind radiators, which allows fresh air to warm up a little when it enters the room. The diameter of the holes is usually in the range of 6-10 cm. According to the types of construction, valves are divided into several types. Some, for example, have a plug that can be opened manually if necessary. More modern models are equipped with special sensors that can respond to changes in the level of humidity in the room, at the right time opening a valve that lets in fresh outdoor air. Many valves have a set of filter elements.
In most cases, natural ventilation in old houses is not able to provide required volume fresh air, so many people install air conditioners. This device cannot completely replace the ventilation system, but it can purify and humidify the air in the apartment.
Forced ventilation in a panel house
Forced ventilation comes to the rescue in cases where the natural is not able to cope with the tasks assigned to it. It is impossible to completely install it on your own, since in each case its project has its own characteristics. In the event that you need to install ventilation in one-room apartment, you can purchase a simple monoblock device.
For the most good ventilation each room will definitely require the installation of air ducts, the installation of which can be carried out by any person. Usually ducts are installed under false ceiling or built into walls.
Natural ventilation channels
For effective ventilation, Each room in the house must have two ventilation devices: one is for air supply, the other is for removing air from the room.
Every room in a house or apartment equipped with a supply and exhaust device for natural ventilation according to one of three options:
- Supply valve in a window or outer wall for air flow. overflow hole to an adjacent room with an exhaust duct for air removal (hole in a door or an internal wall, partition).
- For air flow overflow hole from an adjacent room with a supply valve, and exhaust channel
- Inlet valve for inflow, and exhaust channel ventilation to remove air.
Check whether in the house or apartment where you currently live, whether all rooms have supply and exhaust devices ventilation?!
In which rooms it is necessary to make exhaust ventilation ducts
Exhaust ducts for natural ventilation must be provided from the following premises of the house:
- Sanitary facilities - bathroom, toilet, laundry.
- Kitchens.
- Dressing room, pantry - if the doors of the premises open into the living room. If the doors open into the corridor (hall, kitchen), then one of two things can be done: arrange an exhaust duct from the premises or install an inlet valve in a wall or window.
- The boiler room must have both a ventilation duct and a supply valve.
- From rooms separated from rooms with a ventilation duct by more than two doors.
- On the floor above the first floor, subject to availability entrance doors from the stairs to the floor - ventilation channels are made from the premises indicated above, or (and) from the corridor, hall.
- On the floor above the first, in the absence of entrance doors from the stairs to the floor, each room on the floor is equipped with both a ventilation duct and a supply valve.
In other areas of the house that do not have exhaust ducts for natural ventilation, be sure to install an inlet valve in a window or in a wall and an overflow hole in an adjacent room.
In addition, natural ventilation exhaust ducts are arranged for ventilation:
- Sewer pipe riser.
Building rules (clause 6.5.8 of SP 60.13330.2016) require in residential buildings for premises that house gas equipment (gas boilers, water heaters, cookers, etc.), provide for mechanical forced exhaust ventilation and natural or mechanical supply ventilation.
Location and dimensions of ventilation ducts
The minimum side dimension of the natural ventilation duct is 10 cm., and the minimum cross-sectional area is 0.016 m 2., which roughly corresponds to the diameter of a standard ventilation duct pipe - 150 mm.
Channel minimum size will provide air extraction in the amount of 30 m 3 / hour at length vertical pipe over 3 m. To increase the performance of the hood, increase the cross-sectional area of the channel or the length of the channel. Channels less than 2 m. do not provide the necessary intensity of natural ventilation.
In practice, the length of the ventilation duct on the floor is usually set by design considerations - the number and height of the upper floors located above, the height of the attic, the length of the pipe above the roof. On the floor, the length of all channels must be the same. This is done so that the traction force in each channel on the floor is approximately the same.
The cross-sectional dimensions of the channels on the floor are often made the same, but for structural reasons it is more convenient. The performance of the ventilation channel in a particular room of the floor is adjusted by choosing the size of the ventilation grille.
Ventilation channels from the premises of the house on different floors are placed side by side, combining them into a block of ventilation channels.
For constructive reasons, they try to lay several ventilation ducts from the premises of the same floor side by side, in one place they create a block of ventilation ducts.
Block of ventilation channels in stone houses usually placed inside the carrier inner wall at home or attached to the wall.
The block is laid out from masonry materials, for example, bricks. In brickwork, it is convenient to make channels with a cross section that is a multiple of the size of the brick, taking into account the thickness of the seams - 140x140 mm. (1/2 x 1/2 bricks, 196 cm 2) or 140x270 mm. (1/2 x 1 brick, 378 cm 2)
Expanded clay concrete ventilation block, two-channel 390x190x188 mm. Flow area of one channel 168 cm 2 
Concrete blocks for laying ventilation ducts in a private house. Block height 33 cm., width 25 cm., wall thickness 4 cm. Flow area of one channel 12x17 cm. (204 cm 2)
They release hollow concrete blocks specially designed for laying ventilation ducts.
A block of ventilation ducts made of masonry materials must necessarily be supported by a foundation or reinforced concrete floor.
In other cases, for example, in wooden or frame houses, a block of ventilation ducts is assembled from plastic or galvanized steel pipes. A block of pipes is closed with a box.
How to merge multiple channels into one channel
In a private house, the number of channels is small, so there is no need to combine air flows from several channels (rooms or floors) into one, as is often done in apartment buildings. Each channel of natural ventilation in a private house should begin indoors and end at the head on the roof. Any combination of two or more channels impairs ventilation performance.
In some cases, however, there is a need to combine several channels, combine them into one common channel of natural ventilation.
Read: Ventilation channel performance
Performance of a single exhaust ventilation duct with a section of 12x17 cm.(204 cm 2) from concrete blocks, depending on the height of the channel and the temperature in the room:
Productivity of channels of natural ventilation with a section of 12 x 17 cm.(204 cm 2) depending on the height of the duct and the temperature in the room (at an outdoor temperature of 12 about C)
To determine performance for intermediate values of channel height, plot the dependence on the axes: channel height and performance.
Similar tables can be found for ventilation ducts that are made of other materials.
However, for ventilation ducts of the same section (204 cm 2), but made of other materials, the performance will differ slightly from that indicated in the table.
For a channel of a different section, the performance value from the table can be proportionally increased or decreased.
To increase the performance of a ventilation duct of the same height, it is necessary proportionately increase the cross-sectional area of the channel. To do this, for example, choose a concrete block with a hole bigger size, or use two or three channels of the above size for ventilation of one room.
Calculation of natural ventilation of a private house
The building regulations specify the minimum required capacity of natural ventilation ducts. Usually people feel better when more fresh air is supplied to the room than specified in the norms. The performance of a natural ventilation duct is highly dependent on atmospheric and other variable factors (air temperature inside and outside, wind pressure and direction, resistance to air flow into the room). All this suggests that for a private house, it makes no sense to scrupulously accurately perform the calculation. I recommend rounding the calculation results in the direction of greater productivity of natural ventilation channels. During operation, if necessary, throughput channel can be easily reduced.
The calculation of natural ventilation is carried out in order to determine the size of the ventilation ducts based on the volume of air removed.
When determining the volume of air removed through the channels of natural ventilation, it is taken into account that in rooms with supply valves Air enters from the street, then this air flows into rooms with exhaust ducts, and is removed through the ducts again to the street.
The calculation is carried out for each floor houses in the following order:
- Guided by the standards (see), determine the amount of the minimum volume of air that must come from outside for ventilation all rooms with supply valves - Q p, m 3 / hour.
- According to the standards, the sum of the minimum volume of air that must be go outside for ventilation all rooms equipped with an exhaust ventilation duct - Q in, m 3 / hour.
- Compare calculated minimum values air flow from the street (Q p, m 3 / hour) and leaving for the street (Q in, m 3 / hour). Usually one of the values is greater than the other. The larger of the two values is taken as the minimum design capacity of all exhaust ventilation ducts on the floor- Q p, m 3 / hour.
- Based on the vertical dimensions of the house, the height of the natural ventilation channel on the floor is assigned.
- Knowing the height of the ventilation duct, and the total estimated minimum performance of all ducts on the floor (Q p, m 3 / hour), according to the table (see above), the total number of standard channels from concrete blocks is selected. The total performance of the selected number of standard channels must not be less than Q p, m 3 / hour.
- The selected number of standard channels is distributed between the premises of the house, which must be equipped with exhaust ventilation ducts. When distributing, the need to ensure standard air exchange in each separate room with ventilation duct.
An example of calculating the natural ventilation of a private house
For example, let's calculate natural ventilation in one-story house With with total area floors 120 m 2. The house has five living rooms with a total area of 90 m 2, kitchen, bathroom and toilet, as well as a dressing room (pantry) with an area of 4.5 m 2. Room height - 3 m. The house is made with natural ventilation of the underground space through the ventilation duct. The height of the ventilated space under the floor 0.3 m. We use concrete blocks for the installation of ventilation ducts - see above.
Fan at the entrance to the natural ventilation duct
Continuation: for the next
