To create comfortable conditions, a sufficient influx of fresh air is necessary. If the air exchange system, the air exchange system may occur in the ventilation of the private house, which does not affect its microclimate.
In this case, it is necessary to understand and eliminate the causes of changes in the flow direction. Let's deal with the reasons for the occurrence of reverse thrust in the ventilation system of the house and how to eliminate them.
Reverse thrust occurs in the presence of miscalculations in the design of the ventilation system or insufficiently qualified execution. But since the air has well-studied physical properties, it is easy to reveal the causes of the origin of the problem and find ways to eliminate it.
When modeling air exchange for small volumes that are characteristic of private houses, you can neglect such parameters aerial As a compression ratio and uneven density.
In this case, the main physical law of the supply and exhaust ventilation can be formulated as follows: the difference in the volume of incoming and outgoing air for any period of time is zero.
Exhaust ventilation is installed in places of the largest cluster of polluting aerosols. This is a bathroom, kitchen and office space. Some hoods are supplied with fans for a compulsory increase in the volume of the removed air.
The supply ventilation is installed in residential rooms for receipt of fresh air to the place of permanent stay of people. As a rule, it is forced type with predetermined volumes of the incoming flow.
This is necessary to accurately maintain microclimate parameters, such as temperature, humidity and oxygen mode.
Before designing the air-circuit system or implementing new ventilation equipment, it is necessary based on a similar scheme to calculate and analyze the capabilities of the implines and exhaust to skip the resulting volume of air
Thus, most often the volume of air intake in different places of the house are fixed, and the distribution of the emerging air along the holes variable.
If at a certain point in time, part of the exhaust system passes the stream greater than ensues the supply ventilation, the missing volume is compensated through holes intended for air release.
Before installing the hoods, it is necessary to carry out simple arithmetic calculations that will show the air balance with various combinations of devices.
To prevent such a scenario, it is necessary when developing a ventilation system to perform the following set of actions:
- on each exhaust hole to establish a check valve to prevent air inflows through it;
- organize one or more backup supplies of a natural type to compensate for missing volume.
The cross-section of the holes in the backup supply devices must be calculated in such a way that they can total compensate for the maximum amount of missing air. Each of them must be provided to eliminate air outflow. This is fraught with icing and blocking the implines in winter.
Unaccounted air exchange with the street
Filtration is introduced its role in the air balance of the house - uncontrolled paste air through slots and loosening. If this phenomenon is intense, it is impossible to carry out accurate calculations of the parameters.
In addition, infiltration (filtering directed inside) allows you to penetrate the air into the room without processing it with dust filters and without heating to the desired temperature in winter. Therefore, this phenomenon needs to completely eliminate or make its effect on the overall air turnover.
Air filtration through looseness is easy to detect in winter with a thermal imager. Filming indoors will show cold places of infiltration, and outside - warm places of exhaustration
Open windows, balconies and mansard doors create an additional air exchange. It is impossible to securely reliably, since the speed and even the flow vector depends on the set of factors, primarily the outer and internal temperature, as well as the direction and intensity of the wind.
The only solution to the occurrence of reverse thrust in the air ducts may be the installation of check valves.
In the cold time, the chimney is an additional exhaust power supply device. Along it, hot airs with combustion products comes out, making a significant contribution to the total value of the exhaust flow.
The amount of air emerging through the chimney depends on the power of the boiler. It is easy to calculate it for factory products, since there are tables in the instructions in which the minimum chimney cross-section and the release rate of combustion products for a particular model are indicated.
If the furnace or boiler is made independently, the approximate value of the volume of the air removed must be taken from the technical documentation similar to the parameters of the device.
The technical documentation for the boilers may indicate the need for air consumed. If there is no such information, then you need to multiply the expiration rate of flue gases to the chimney section
If you consider chimney as an exhaust channel, then its specificity is the inability to install the check valve on it. An alternative can be an integrated smoke, but only if its installation is technically possible. Then heating can be included in the model as an exhaust with a fan.
To calculating the balance of air in the presence of chimney, it is necessary to approach responsibly. Even a single reverse stream is able to completely spoil the interior of the room. In addition, with a large flame there is a risk of fire, as well as the possibility of poisoning people of combustion products.
Typical problems with air exchange
Reducing the flow rate relative to the estimated even in one adhesive or hood leads to the imbalance of the air circuit in the house. This affects the operation of other devices in which a compensatory change in stream parameters occurs, including a reverse may occur.
Therefore, it is necessary to examine all the places of receipt and outflow of air and then it turns out to find out why the general ventilation works by directing the flow to reverse side.
Reduction of incoming air
Reducing the air velocity in the supply unit with a fan may be caused by the following reasons:
- Loss of engine power, fan vibration and other signs of equipment wear. It is necessary to repair and eliminate the identified malfunctions.
- Failure to configure system parameters. You need to reconfigure the system or repair the control unit.
- Filter pollution. The most common cause of reducing the power of the supply ventilation. Cleaning or replacement of the liner is required.
- Fan pollution. As a result of the pollution of pollutants, the geometry of the blades varies. Then, with the same number of revolutions, the pressure characteristic of the device decreases.
- Reducing a living channel cross-section. It can occur in any node of the supply system through which air passes: pipe, recuperator, calorifer, etc. It is necessary to carry out their regular service cleaning.
- Partial or complete closing of an external lattice. The filter grille can be clogged with insects, foliage and other trash. In winter, its snow is noticed. Therefore, it is necessary to periodically check its bandwidth.
With natural supply ventilation, a frequent reason leading to an insufficient influx, and sometimes the emergence of the reverse thrust is the effect of discharged air from the street side.
Such a phenomenon may occur with a leeward side of the building. It can be eliminated, using special fences near the air intake hole.
To prevent the creation of the discharge zone near the supply opening, you need to put a small fence. However, winter will have to clean the snow more often
Hooding faults and their elimination
The reasons for bad work of the forced type extract are the same as the supply device. But most often the problem occurs not due to filter contamination (which are not always installed on the exhaust), and due to the narrowing of the living section of the ventilation channel.
Unlike fresh air, the removed stream carries moisture, pairs, small drops of fat, which stick to the walls of the ventilation channel.
Over time, on the inside, anti-aerodynamic resistance are formed on the inside, which leads to a decrease in the exhaust air volume. At the same time, the exhaust device itself can work properly.
The rules for the location of the pipes on the roof are quite simple, so you can remove the ventilation through the roof almost anywhere. It will only be necessary to observe the desired height.
Often there is a situation where, when building a house, all the rules for the placement of ventilation exits were observed, but in the future there was a change in the landscape, which led to the formation of the windows zones:
- modification of the geometry of the roof (including the installation of the satellite antenna);
- building in the immediate vicinity of high build;
- grounding near wood.
In this case, you can transfer the output of the ventilation channel to another place, increase the height of the pipe or try to remove the cause that creates the windband zone.
You also need to check the quality of work. If it has mechanical damage or as a result of poor attachment changed its position relative to the pipe, it may also cause problems. To significantly increase the traction can be replaced by an ordinary deflector on rotary.
Reverse in the system of air ducts
In private houses, the system of air ducts, connecting several exhaust holes with one ventilation shaft, was distributed. Some points can be equipped with forced air intake devices, such as kitchen hood or channel fan.
The occurrence of reverse thrust in one of the branches of the air duct can be caused not only to the problems described above with the overall exhaust, but also by the redistribution of the flow vector inside the ventilation channel system.
The operation of powerful hoods creates a high-speed flow and increases the pressure in the air duct. Therefore, the air rushes to all open ventilation holes.
To prevent such a scenario, the setting of check valves is used for each of the branches of the air duct. These devices skip the flow in one direction and close the channel cross-section at its reverse.
As a rule, when installing the air duct, specialists set check valves. It may not be in the case of an additional punching branches, if the installation was produced later. In this case, you need to install such a device. You can do it yourself without restructuring the entire system of air ducts.
For this you need:
- Purchase valve suitable sizes.
- Disassemble the system of air ducts in the place where it will be installed.
- Cut off part of a rectangular canal or flexible pipe The size of the valve length.
- Collect the system with a valve.
- Check her tightness.
If the check valve is set, but reverse thrust occurs, this means that the device is faulty.
There may be several reasons:
- the occurrence of the slit in the membrane, sash or valve shell;
- wear of the moving parts, resulting in closing the sash or membrane;
- dry garbage hit (for example, a piece of paper or a large beetle), which interferes with the complete closure of the device.
In any case, it is necessary to disassemble a part of the duct and remove the valve. If it is impossible to repair it, you should purchase a device of the same size and assemble the air duct.
Conclusions and useful video on the topic
How to make an inflow ventilation to prevent feedback in hoods:
The correct work of exhaust and, especially, the supply ventilation is the key to the absence of reverse thrust. To do this, it is necessary to periodically inspect the devices and carry out the flow rate for them.
If after reading the material you have questions or you found inaccuracies, leave, please comments in the block below. Maybe you also have a problem in the work of the ventilation system? Describe it and we will try to cope with it.
According to the construction standards, the apartments should be equipped with ventilation, whose task is to remove from the premises like a kitchen, toilet and a bathroom polluting air.
The ventilation process lies in air exchange, constant circulation, air movement.
How should a serviceable ventilation system work
A man per day makes many movements by residential premises, and many of his actions contribute to the saturation of the atmosphere of the apartment, air pollution. With good ventilation, air pollution turns out to be unnoticed because it completely leaves the premises. But if the work of ventilation is broken, it will be extremely unpleasant for people living in the apartment.
To understand how high-quality Ventkanals in the apartment perform their work, it is optional specialist. You will not need any complex instruments for checking - one sheet of newspaper paper is enough. Open the window in any of the rooms in the apartment and attach a newspaper sheet in a straightened form to a decorative lattice closing the ventilation inventory of the kitchen or bathroom. If the sheet pulled to the grid, everything is in order with ventilation. If he deviated from the lattice in the opposite direction, the thrust turns out, respectively, the reverse, that is, the air exchange is made incorrectly, and people living here breathe unwanted smells.
If you have double-glazed windows, ventilation should be checked exclusively with open windows.
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Ventilation in high-rise buildings
In ordinary apartments, ventilation is not mechanical - only the imputy-exhaust. The air exchange rates are still at the stage of the preparation of the project by which the house will be built, calculated for the ventilation of the natural type. In order for the air from the rooms to the ventilation moves, he first needed from somewhere to appear. According to the adopted standards, it is necessary to enter it through the slots in the frames or door structures.
As windows of metal plastic with a hermetic design, and modern strong metal doors, equipped with seals, were widely used relatively recently. On their excellent performance characteristics are known to all. The problem arising from their use is that with the emergence of new construction technologies, the former norms are preserved. According to these standards, the air in the housing is included through small holes, slots, tiny holes, and they simply excluded in new window and door structures. With the complete tightness of the premises, the conditions for good operation of the ventilation system will be somewhat difficult.
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Ventilation disorders when using exhaust
People living in apartments are often faced with the same troubles concerning ventilation. In typical apartments, where the PVC windows and a deaf door are supplied, there are usually two channels for which the exhaust air should be removed. Of these, one serves to carry out ventilation in the bathroom, the other is designed to clean the atmosphere of the kitchen, and in some places even the hood for the stove.
The tenants of such apartments sometimes face an unpleasant phenomenon when from the venting hole in the toilet blows in the opposite direction. Sometimes the reason for this is the regular use of an exhaust device.
Modern exhaust machines work with sufficient power so that when you turn on to skip the main part of the air apartment. As a result, it can be cleaned, and all the channels for which the additional (doors and windows) could have come closed. With such a violation, the influx of air in the apartment from the bathroom is inevitable.
Even if in the ventilation channel of the toilet everything is in order, it is completely in good condition and perfectly functions, with insufficient air in the rooms there are reverse thrust. Ventilation of apartments on each other is combined into one system, and smells from the lower floors can begin to enter the rooms.
With such a problem, you can cope very simply - for a while when the exhaust is turned on, the windows should be opened. If indoors are installed sealed window and door designs, the air will fall inside through the open window. You should not rely on the operation of the supply devices - they can compensate for the air remote through the ventilation channels, but to provide them with a full exhaust power - the task for them is almost unbearable.
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Other possible causes of faults
The problem may consist not only in this. There are other subtleties in the ventilation device, and if you do not know about them, the reason for the reverse thrust from unwanted places you can search for quite a long time. The first thing that comes to mind when air starts blowing from the vent holes, the canal clogged. Sometimes it happens. But often, with a thorough check of Ventkanal with incorrect behavior, it turns out that it is absolutely clean, the mine emerging to the roof is in excellent condition. In the attic there may be still connecting boxes, and if they are also working, it's just not why. And the easiest explanation of what is blowing, the installation of its lattice on the passage canal becomes. In one channel, several vertically apartments are connected.
In order for the ventilation could function as it should, at the beginning of the apartment, the apartment should stand the plug. At the air, which is set to the channel through the grid, only direction upwards should be opened to exit. There should be no moves in the lower part - the canal should be overlap. If this state is violated, the channel issues a reverse craving.
It turns out about the following picture. Instead of a properly functioning ventilation system with a shared mine and satellite channels, there are several transit branches in the house. This situation is not particularly noticeable on the lower floors, but on the upper can turn into a real problem.
The airflow rising by the channel flies past the ventholesale, while he either gives a reverse craving, or becomes an obstacle to the path of exhaust air. The installed plug does not skip the lower air flow, directing them through a special hole in the collection channel. It helps to start the ventilation process from scratch, absolutely unhindered, without the fight against other air flows - ideally should be that way.
As already mentioned, the reason for the ventilation fault is not alone. For example, the cause of the emergence of the wind, which blows from the outstands in the toilet in the opposite direction, can be the location of the apartment. The inhabitants of the upper floors of apartment buildings are more often than others, it is familiar to such a nuisance like a reverse thrust in the toilet.
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What can be done to improve air exchange
In order for the system to perform a good air exchange, the air should be ensured to pass through the channel at least 2 m in the vertical direction. So it turns out on all floors, but not on the latter - there in many cases will interfere with the indoor indoor. You can use one of the following ways to display ventsystems from the apartment.
The first option is when the channels are simply displayed on the roof in the form of the pipe. Almost all buildings built before the twentieth century, created this way. When there were a lot of high-altitude houses, it was gradually refused from this method. Another popular method - the elements of the ventilation that have reached the attic were hidden by horizontally located boxes, hermetically closed. They were connected to the mine, and she walked out and went over the roof. In modern buildings, another method is used more often: the ventilation channel is displayed on the attic, which can be considered as a vents, after which it comes out through a shaft.
When using the last method, the movement of air is carried out like this: it is going from all floors, goes along the channels up, comes to the attic and enters the connecting box. The air flow hits his cover and deflects in the direction of the mine, but with a small inner section of the box, it may have too high pressure in it, the air will try to exit any suitable hole, even even in the opposite direction.
With the usual design of such outputs, there may be two - ventilation mines and the upper floor channel, it is intended for these purposes and is located more conveniently. Sometimes it turns out that the section of the box is sufficient, and the roof is arranged too low. Then the following happens: the air flow due to the low location of the lid does not have time to change the direction and deviate towards the mine, it is hung with the ventilation of the upper floor, which is deformed and passes into the apartment all air and smells from the floors below.
It is not easy to fight this inconvenience, but perhaps. To do this, you can use any of two ways - global or local.
With a global correction method, you will have to change the cross section of the horizontal connecting box in the attic, increasing its height of 2-3 times, and inside the design, it is suitable for devils called. Perform such actions should be a professional worker. It should be borne in mind that the box cross section is better not to expand if the same structures are connected to the ventilation mine.
When selecting a local method of floor channels, which is separated from common design And roll in the mine over the connecting box. Separate channels must be insulated, it will help not to break the temperature and humidity in the attic. If everything is done without disturbances, ventilation in the apartment will work as it should be.
There is another option to remove air, in modern residential premises it is used more often. In most multi-storey buildings, ventilation work is carried out precisely on this principle. Residents of the last floors often have the problem of too weak traction, and not that it is reverse. Normally, the air flow before merging with the general, should be vertically pass 2 m.
But when the housing is located on one of the last floors of the structure, it turns out not quite so. The air fell into the channel moves vertically by about 30 cm, after which it is diverted, not time to gain speed. Therefore, it is impossible to say that the air flows are missing, but in the upper apartment, with such a movement, the air exchange is strongly reduced. If you open the doors in the attic, it turns out a draft, which is why the thrust in the area of \u200b\u200bthe upper floors is capable of changing. To make it possible, for the upper floors it is necessary to build individual channels. Pipes with a suitable diameter are put on the outlet holes, the joints are well deceived by alabaster. The optimal height for the withdrawal of pipes is approximately 1 m. Then they need to be sent towards the shared mines, slightly tilt. With this location, the air flow coming down next to the pipes, captures and pulls the air from the upper floors.
If you live in a multi-storey building, you may know that it is often from the ventilation grilles in the toilet and in the kitchen blows with cold air. Especially such a phenomenon is noticeable in cold period time and in strong winds. From here there is a question why blows from ventilation and what to do to prevent this. To deal with this, first discuss the principle of the ventilation system.
As practice shows, the cold air blows in the bathroom, which is combined with a bathroom. This room is bordered by a staircase, so here is not very warm, and due to the tributary of cold air it can become even cold. To deal with the way, it should be understood that natural supply and exhaust ventilation were originally manufactured. In those rooms where the environment is the most dirty, exits in vertical drawing of hoods are settled.
It is known that the inner air is warm outdoor, respectively, it goes up the exhaust mine. This explains the formation of natural traction. The more temperature difference and height between the mouth of the inlet opening in the apartment and the exhaust pipe, the stronger this line. Plus, there is an additional influx of fresh air through the openings of window wooden blocks.
The ventilation made on this principle can very quickly fail. The following factors can contribute to this:
- Strong gusts of wind with a destroyed protective umbrella and shaft headside.
- Incorrect selection and installation of fans instead of ventilation grids.
- Sealing premises after replacing windows.
Very often all these three factors are triggered at the same time and, in this case, the ventilation will blow back to the apartment with a cold stream and plus to this with an unpleasant odor.
Installed metal-plastic windows, in contrast to wooden practical, do not let air. For this reason, the interval is stopped into the house. Therefore, the hood work becomes wrong. In this case, tipping the thrust in one mine at the expense of another channel.
Speaking in other words, exhaust mine, big cross section And high performance (in the kitchen) does not find another source of air inflow, tipping over the craving in another mine (in the toilet). As a result, both in winter and summer, ventilation works in the opposite direction, filling the room with cold air.
This effect is significantly enhanced if you mount the axial fan or kitchen exhaust and connect them to an existing ventilation system. The fan will simply drag the air from one channel to another. The problem may be the wind gusts, especially if the mouth of the canal or umbrella is destroyed. Therefore, the flow of cold will be intensified.
Such an imbalance in the work of ventilation may occur in private houses. Usually, in them, the top of the exhaust mine is located in the area of \u200b\u200bthe vacuum, which is formed by the ridge of the roof. The reason for the violation of the construction standards and the discrepancy between the height of the channel.
There are other reasons for violations of ventilation, as a result of which the inverse thrust arises. For example, the ventilation canal clogged. But with a thorough investigation, Ventcanal is clean. Mine that goes to the roof has a perfect condition. And in the attic can even be connective boxes. If they are also working, then what's the problem? The simplest explanation is that lattices are installed on the passing channel. At the same time on the same channel, located on one vertical of the apartment installed several lattices. Therefore, for normal functioning, the first thing in Ventkanal, namely, in its beginning, the plugs should be installed. The air that falls through the grille into the channel should have only one direction - up. In the lower part of the channel, no moves should remain. If this is not, there is no reverse thrust.
Especially this problem will feel the tenants of the last floors. The air flow by the channel by the ventilation grille becomes an obstacle to the air outlet from the apartment or gives a reverse craving. And, as a time, the plug levels the air flow from below, directing it through a special hole in the national channel. Ideally should be like that!
So, the reverse thrust in multi-storey houses is frequent phenomenon. From this article it was possible to know the reasons for this. Therefore, if you are planning a major overhaul in the apartment, then be sure to make sure that your ventilation system works properly, and all measures have been taken so that the reverse traction does not occur. If you know other methods of eliminating this malfunction, then be sure to write to us about it, leaving a comment at the end of this article.
The presence of errors in the residential building can lead to different unpleasant phenomena, one of which is the return rod in ventilation. The purpose of the ventilation system is to remove the contaminated air, and the inflow must be performed through the windows.
However, with violations, ventilation is incorrect, and brings polluted air from other consumers to rooms. To eliminate this problem, a plug is applied with a check valve - it does not allow air flow to fall into the apartment, and they move in a shared mine.
Evaluation of the operation of the ventilation system
To find out what the deviations in the ventilation are related to, it is required to invite independent specialists who perform the operation of the system. They are checked by the obtained indicators with the data given in regulatory acts. Specialists describe in detail the deviations in the operation of the ventilation system, and make a conclusion about the performance of the system, and also give recommendations to the customer.
Examination can be divided into three stages:
- Checking the entire design documentation regarding the ventilation system. At this stage, experts evaluate the rationality of the use of constructive solutions and the existing equipment, the correctness of its use and the compliance of documentation with construction standards and gta stations.
- Check mounting work. This stage is to assess the quality of the mounted elements of the air pipe, the channel and other equipment.
- Search for breakdowns and disadvantages of work. The state of the system and the performance of it as a whole is estimated. The real indicators of air outflow with data embedded in the project are compared.
To determine the reasons not proper work The ventilation system, experts check the air parameters in the premises. To search for places in which the channels of natural ventilation are unauthorizedly blocked, applied by a video endow.
Causes of reverse thrust
Improper operation of the ventilation system in the apartment can be caused by various reasons. The most simple and obvious can be determined by inspection of the furnace or fireplace. To understand the thrust violations, you should find out the location of the pipe and exit to the roof.
If the primary inspection did not give tangible results, it is necessary to look for the causes of the improper operation of the system inside the apartment.
In many cases, the reasons for the reverse thrust in ventilation are improperly or insufficient air inflows inside the room. The problem arises due to modern hermetic windows. Unlike old wooden windowsFor which most of the multi-storey houses designed, plastic windows do not let the air inside the apartment. To solve this problem, it is recommended to establish supply valves or an additional ventilation system that provides air flow.
For furnaces or fireplaces to work correctly, they require a permanent air flow inside the room. It should be borne in mind that ventilation channels work in more active mode compared to chimney. When using a small cross-section pipe, the air flow inside them has a high speed due to the fact that air heating occurs quickly.
If there is a staircase in the apartment or cottage, it should be considered when designing and creating a ventilation system. The staircase, in its essence, is a huge tube at which air moves. With errors in the project, it can lead to a change in the direction of flows in the ventilation channels.
It should be borne in mind that the curved staircase has a smaller impact on the operation of the ventilation system than direct.
Also an important factor in violation of the proper ventilation is a powerful kitchen extractor. The effect of its action is enhanced if it is located not far from the fireplace. The most productive models of extracts are able to distill to 1.2 thousand cubic meters. m 3 air per hour of work. With such a volume, neither the fireplace networks nor the air lines are cope with the fireplace.
Common causes of reverse ventilation traction in the apartment:
- Features of the location of the pipe on the roof. There is a chance of finding a pipe in the zone that "Wind shadow", when the protruding parts of the house closes air flows. Also the wind can blow in opposite side, preventing air movement in the pipe.
- Clogging of ventilation channels. They fall into them a different garbage, ice and snow, soot and consequences of birds living on the roof.
- Cutting in the channels of a large volume of steam or cold air, which prevents air movement.
- Improper work of extracts, compressors and fans. A similar problem occurs due to drafts, which blow in large rooms that do not have partitions. IN apartment houses The situation is often found when the intensive removal of air from one apartment leads to the occurrence of reverse thrust in another.
Restoring air regulation
To figure out in detail why in the ventilation is a reverse thrust, you need to analyze all the important parameters. Disrupt the system can many factors external environment, such as the atmosphere pressure and humidity, convection flows, phenomena of isothermia inversion.
One way to solve is the placement of a deflector, which is a mechanical fan that performs air seats from the mine. As a stream amplifier can be a sewer regulating the reverse craving. In some cases, it is enough to open the windows to spark a good room.