To date, in modern construction there are branches in which research is being carried out to improve the technology of construction, they also improve the quality during operation, and the air exchange of rooms in a building is no exception. Problems in this area are relevant and are solved by selecting the multiplicity for the ventilation system. Full-scale tests are carried out and standards are written based on them. The most successful country in this business is the United States. They developed the ASHRAE standard, using the experience of other countries, namely Germany, Denmark, Finland, and their own scientific developments. The post-Soviet space also has a developed analogue of such a document. In 2002, ABOK developed standards for “air exchange norms for public and residential buildings”.

The construction of modern buildings is carried out with the calculation of increased insulation and high tightness of windows. Therefore, optimal air exchange is very important in such cases in order to comply with sanitary and hygienic standards and the appropriate microclimate. It is also important not to damage energy efficiency, so that in winter all the heat is not drawn into the ventilation, and in the summer - cool air from the air conditioner.

To determine the calculation of air exchange in rooms other than hospitals, a new method has been created and is described in ASHRAE publication 62-1-2004. It is determined by summing up the indicators of the value of fresh outdoor air, which is supplied directly for breathing, taking into account the area of ​​\u200b\u200bthe room falling on one person. As a result, the value turned out to be significantly lower than the later edition of ASHRAE.

Air exchange rates in residential buildings

When carrying out the calculation, it is necessary to use the data in the table, provided that the level of saturation of harmful components is not higher than the MPC norms.

Premises	Air exchange rate	Notes
Living sector	Multiplicity 0.35h-1, but not less than 30 m³/h*person.	When calculating (m 3 / h), by the multiplicity of the volume of the room, the area of ​​\u200b\u200bthe room is taken into account
	3 m³ / m² * h of residential premises, with an apartment area of ​​\u200b\u200bless than 20 m² / person.	Rooms with air enclosing structures require additional exhaust
Kitchen	60 m³/h for electric cooker	Air supply to living rooms
	90 m³/h for using a 4-burner gas stove
Bathroom, toilet	25 m³/h from each room	Same way
	50 m³/h with a combined bathroom
Laundry	Multiplicity 5 h-1	Same way
Dressing room, pantry	Multiplicity 1 h-1	Same way

In cases of non-use of the premises for housing, the indicators are reduced as follows:

• in the area of ​​residence for 0.2h-1;
• in the rest: kitchen, bathroom, toilet, pantry, wardrobe for 0.5h-1.

At the same time, it is necessary to avoid the ingress of flowing air from these premises into the living rooms, if it is present there.

In cases where the air entering the room from the street travels a long distance to the exhaust, the air exchange rate also increases. There is also such a thing as a delay in ventilation, which implies a lag in the entry of oxygen from the outside before it is used indoors. This time is determined using a special diagram (see figure 1), taking into account the lowest air exchange rates in the above table.

For example:

• air consumption 60 m³/h*person;
• housing volume 30 m³/person;
• delay time 0.6 h.

Air exchange rates for office buildings

The standards in such buildings will be much higher, because ventilation must effectively cope with the large amount of carbon dioxide emitted by office employees and equipment located there, remove excess heat, while supplying clean air. In this case, there will not be enough natural ventilation, the use of such a system today cannot provide the required hygienic and air exchange standards. During construction, hermetically sealed doors and windows are used, and the panoramic glazing device completely limits the ingress of air from the outside, which leads to air stagnation and a deterioration in the microclimate of housing and the general condition of a person. Therefore, it is necessary to design and install special ventilation.

The main requirements for such ventilation include:

• the possibility of providing a sufficient volume of fresh clean air;
• filtration and elimination of used air;
• no excess of noise standards;
• convenient management;
• low level of energy consumption;
• the ability to fit into the interior and have a small size.

In conference rooms, additional air inlets are required, and an exhaust must be installed in toilets, corridors, and copy rooms. In offices, a mechanical hood is installed in cases where the area of ​​\u200b\u200beach office exceeds 35 square meters. m.

As practice shows, with an incorrect distribution of a large air flow in offices with low ceilings, a draft is created, and in this case, people demand to turn off the ventilation.

Organization of air exchange in a private house

A healthy microclimate and well-being depend largely on the proper organization of the supply and exhaust system in the house. Often, during design, ventilation is forgotten or given little attention, thinking that one hood in the toilet will be enough for this. And often the air exchange is organized incorrectly, which leads to many problems and poses a threat to human health.

In the case when there is insufficient output of polluted air, there will be a high level of humidity in the room, the possibility of infection of the walls with fungus, fogging of windows and a feeling of dampness. And when there is a poor inflow, there is a lack of oxygen, a lot of dust and high humidity or dryness, it depends on the season outside the window.

Properly arranged ventilation and air exchange in the house looks like this, as shown in the figure.

The incoming air in the dwelling must first pass through the window or open window sashes, the supply valve is located on the outside of the dwelling wall, then, passing through the room, it penetrates under the door leaf or through special ventilation openings and enters the bathrooms and kitchen. It takes longer to go out through the exhaust system.

The method of organizing air exchange in the use of ventilation systems differs: mechanical or natural, but in all cases the air enters from residential areas, and exits into technical ones: a bathroom, a kitchen, and others. When using any system, it is necessary to arrange ventilation ducts in the inner part of the main wall, this will avoid the so-called overturning of the air flow, which means its reverse movement before, as indicated in Figure 2. Through these channels, the exhaust air is discharged outside.

Why is air exchange necessary?

Air exchange is the flow rate of supplied outdoor air m3/h that enters the building through the ventilation system (Figure 3). Environmental pollution in living rooms comes from sources located in them - it can be furniture, various fabrics, consumer products and human activities, household products. It also happens through gas formation from the effects of carbon dioxide exhalation by a person and other vital body processes, as well as various technical fumes that may be present in the kitchen from gas combustion on the stove and many other factors. Therefore, air exchange is so necessary.

In order to maintain normal air values ​​in the home, CO2 saturation should be monitored by adjusting the ventilation system based on the concentration. But there is a second way, more common - this is a method of controlling air exchange. It is much cheaper and in many cases more effective. There is a simplified way to evaluate it using Table 2.

But when designing a mechanical ventilation system in a house or apartment, you need to make a calculation.

How to check if ventilation is working?

First, it is checked whether the hood is working, for this it is necessary to bring a sheet of paper or a flame from a lighter directly to the ventilation grill located in the bathroom or in the kitchen. The flame or leaf should bend towards the hood, if so, then it works, and if this does not happen, then the channel may be blocked, for example, clogged with leaves or for some other reason. Therefore, the main task is to eliminate the cause and provide traction in the channel.

Description:

The quality of the air we breathe depends on the efficiency of ventilation. Underestimation of the influence of air exchange on the state of the air environment in residential apartments leads to a significant deterioration in the well-being of the people living in them.

Natural ventilation of residential buildings

E. Kh. Kitaitseva, associate professors of Moscow State University of Civil Engineering

E. G. Malyavina, associate professors of Moscow State University of Civil Engineering

The quality of the air we breathe depends on the efficiency of ventilation. Underestimation of the influence of air exchange on the state of the air environment in residential apartments leads to a significant deterioration in the well-being of the people living in them.

SNiP 2.08.01-89 "Residential buildings" recommends the following air exchange scheme for apartments: outside air enters through the open windows of living rooms and is removed through exhaust grills installed in kitchens, bathrooms and toilets. The air exchange of the apartment must be at least one of two values: the total exhaust rate from the toilets, bathrooms and kitchen, which, depending on the type of stove, is 110 - 140 m 3 / h, or the inflow rate equal to 3 m 3 / h for each m 2 of living space. In standard apartments, as a rule, the first version of the norm turns out to be decisive, in individual apartments - the second. Since this version of the norm for large apartments leads to unreasonably high ventilation air consumption, the Moscow regional norms MGSN 3.01-96 "Residential buildings" provide for air exchange in living rooms with a flow rate of 30 m 3 / h per person. In most cases, design organizations interpret this standard as 30 m 3 / h per room. As a result, in large municipal (not elite) apartments, air exchange can be underestimated.

In residential buildings of mass development, natural exhaust ventilation is traditionally performed. At the beginning of mass housing construction, ventilation was used with individual channels from each exhaust grille, which were connected to the exhaust shaft directly or through a collection channel in the attic. In buildings up to four floors, this scheme is still used today. In high houses, to save space, every four to five floors, several vertical channels were combined with one horizontal one, from which the air was then directed to the mine through one vertical channel.

At present, the principal solution for natural exhaust ventilation systems in multi-storey buildings is a scheme that includes a vertical collection channel - "trunk" - with side branches - "satellites". Air enters the side branch through an exhaust opening located in the kitchen, bathroom or toilet and, as a rule, in the interfloor ceiling above the next floor, is bypassed into the main collection channel. Such a scheme is much more compact than a system with individual channels, can be aerodynamically stable and meets the requirements of fire safety.

Each vertical of apartments can have two "trunks": one for transit of air from kitchens, the other from toilets and bathrooms. It is allowed to use one "stem" for ventilation of kitchens and sanitary cabins, provided that the place of connection of the side branches to the collection channel at one level must be at least 2 m above the level of the serviced premises. One or two last floors often have individual channels that are not connected with a common main "trunk". This happens if it is structurally impossible to connect the upper side channels to the main channel according to the general scheme.

In typical buildings, the main element of the natural ventilation system is a floor ventilation unit. In buildings built according to individual projects, exhaust air ducts are most often made in metal.

The ventilation unit includes a section of the main channel of one or more side branches, as well as an opening connecting the ventilation unit with the serviced premises. Now the side branches are connected to the main channel through 1 floor, while earlier solutions provided for connection through 2 - 3 and even 5 floors. The interfloor joint of ventilation units is one of the most unreliable places in the exhaust ventilation system. To seal it, cement mortar is sometimes used, laid in place along the upper end of the underlying block. When installing the next block, the solution is squeezed out and partially overlaps the cross section of the ventilation ducts, as a result of which their resistance characteristic changes. In addition, there were cases of leaky sealing of the joint between the blocks. All this leads not only to an undesirable redistribution of air flows, but also to the flow of air through the ventilation network from one apartment to another. The use of special sealants still leads to the desired result in terms of the complexity of the sealing operation with the inaccessibility of the seam.

In order to reduce heat loss through the ceiling of the upper floor and to increase the temperature on its inner surface, most typical projects of multi-storey buildings provide for the installation of a "warm attic" about 1.9 m high. Air enters it from several prefabricated vertical channels, which makes the attic a common horizontal area ventilation systems. Air is removed from the attic space through one exhaust shaft for each section of the house, the mouth of which, in accordance with SNiP "Residential Buildings", is located 4.5 m above the ceiling above the last floor.

At the same time, the exhaust air in the attic should not cool down, otherwise its density increases, which leads to the overturning of the circulation or a decrease in the exhaust flow rate. At the floor of the attic above the ventilation unit, a head is arranged, inside which, as a rule, the side channels of the last floor are connected to the main one. When leaving the head in the "barrel" the air moves at a high speed, therefore, due to ejection, exhaust air is sucked into it from the side channels of the last floor.

Since the same ventilation units are used in buildings from 10 to 25 floors, for a 10 - 12-story building, the air velocity in the main channel when entering the "warm attic" is insufficient to eject air from the side branch of the upper floor. As a result, in the absence of wind or when the wind is directed to the facade opposite to the apartment in question, it is not uncommon for the circulation to overturn and blow the exhaust air of other apartments into the apartments of the top floor.

Calculated for natural ventilation is the mode of open windows at an outdoor temperature of +5 ° C and calm weather. When the outside temperature drops, the draft increases, and it is believed that the ventilation of apartments only improves. The system is calculated in isolation from the building. At the same time, the flow rate of the air removed by the system is only one component of the air balance of the apartment, in which, in addition to it, the flow rate of air infiltrating or exfiltrating through the windows and entering or leaving the apartment through the front door can play a significant role. Under different weather conditions and wind directions, open or closed windows, the components of this balance are redistributed.

In addition to the design solutions of the system itself and weather conditions - temperature and wind - the operation of natural ventilation is influenced by the height of the building, the layout of the apartment, its connection with the staircase and elevator assembly, the size and breathability of windows and entrance doors to the apartment. Therefore, the norms for the density and size of these fences should also be considered relevant to ventilation, as well as recommendations for the layout of apartments.

The air environment in the apartment will be better if the apartment is provided with through or corner ventilation. This norm according to SNiP "Residential buildings" is mandatory only for buildings designed for III and IV climatic regions. However, at present, even for central Russia, architects are trying to place apartments in the building so that they satisfy this condition.

The entrance doors to the apartments of SNiP "om "Construction Heat Engineering" are required to have high tightness, ensuring air permeability of no more than 1.5 kg / h m 2, which should practically cut off the apartment from the staircase and elevator shaft. In real conditions, achieve the required density of apartment doors It is far from always possible. Based on numerous studies conducted in the 80s by the TsNIIEP of engineering equipment, MNIITEP, it is known that, depending on the degree of sealing of the door porches, the values ​​of their aerodynamic resistance characteristics differ by almost 6 times. Leakage of apartment doors causes the problem of the flow of exhaust air from the apartments of the lower floors along the staircase to the apartments of the upper floors, as a result of which, even with a well-functioning exhaust ventilation, the supply of fresh air is significantly reduced. In buildings with a one-sided arrangement of apartments, this problem is exacerbated. The scheme of air flow formation in a multi-storey building with loose apartment doors is shown in Fig. 1. One of the ways to combat the flow of air through the stairwell and the elevator shaft is the arrangement of floor corridors or halls with a door separating the stair-elevator unit from the apartments. However, such a solution, with loose apartment doors, enhances the horizontal flow of air from one-sided apartments facing the windward facade into apartments with a windward orientation.

Formation of air flows in a multi-storey building

The air permeability of windows of residential buildings according to SNiP "Construction Heat Engineering" should not exceed 5 kg / h m 2 for plastic and aluminum windows, 6 kg / h m 2 - for wooden ones. Their dimensions, based on the norms of illumination, are determined by the SNiP "Residential Buildings", limiting the ratio of the area of ​​​​light openings of all living rooms and kitchens of the apartment to the floor area of ​​\u200b\u200bthese premises to a value of no more than 1: 5.5.

With natural exhaust ventilation, windows play the role of supply devices. On the one hand, the low air permeability of windows leads to an undesirable reduction in air exchange, and on the other hand, to saving heat for heating the infiltration air. With insufficient infiltration, ventilation is carried out through open windows. The inability to adjust the position of the window vents forces residents to sometimes use them only for short-term ventilation of the premises, even with noticeable stuffiness in the apartment.

An alternative option for an unorganized inflow is the supply devices of various designs installed directly in the external fences. Rational placement of supply units in combination with the ability to adjust the supply air flow allows us to consider their installation as quite promising.

Field studies and numerous calculations of the air regime of the building made it possible to identify general trends in the changes in the components of the air balance of apartments under changing weather conditions for various buildings.

Aeromat accommodation options

With a decrease in the outdoor temperature, the share of the gravitational component in the pressure difference outside and inside the residential building increases, which leads to an increase in the cost of infiltration through windows on all floors of the building. More significantly, this increase affects the lower floors of the building. An increase in wind speed at a constant outdoor temperature causes an increase in pressure only on the windward facade of the building. The change in wind speed most strongly affects the pressure drops of the upper floors of tall buildings. Wind speed and direction have a stronger effect on the distribution of air flows in the ventilation system and infiltration rates than the outdoor temperature. Changing the outdoor temperature from -15°C to -30°C leads to the same increase in air exchange in the apartment as an increase in wind speed from 3 to 3.6 m/s. The increase in wind speed does not affect the flow of air removed from the apartment of the windward facade, however, with bad entrance doors, the inflow into them decreases through the windows and increases through the entrance doors. The influence of gravitational pressure, wind, layout, resistance to air penetration of internal and external enclosing structures for high-rise buildings is more pronounced than in low-rise and medium-rise buildings.

In connection with the installation of dense windows in the building, the installation of an exhaust system only turns out to be ineffective. Therefore, to supply the inflow to the apartments, both various devices are used (special aeromats in the windows, which have a rather large aerodynamic resistance and do not let in noise from the street (Fig. 2), supply valves in the outer walls (Fig. 3), and mechanical supply ventilation is designed .

Abroad, mechanical exhaust ventilation systems have become widespread in housing construction, especially for high-rise buildings. These systems are distinguished by stable operation in all periods of the year. The presence of low noise and reliable roof fans (similar fans are also equipped with garbage chute shafts) has made such systems quite widespread. As a rule, air mats are installed in window frames for air flow.

Unfortunately, domestic experience in the use of mechanical ventilation systems common to a building or riser is associated with a number of problems, as evidenced by the example of operation in Moscow of dozens of 22-storey buildings of the I-700A series. According to the state of the air environment, at one time they were recognized as emergency. The result of structural and installation defects, as well as poor operation (non-working fans) is insufficient air removal from all apartments in general and its flow from one apartment to another through a non-working system. Other shortcomings associated with the poor tightness of the systems and the complexity of their installation adjustment were also noted.

In the best position, in terms of fan operation, are apartments with individual fans. These include apartments in a number of typical buildings, where small axial fans are installed in individual exhaust ducts on the top floors.

A large number of complaints about the operation of natural ventilation systems made it legitimate to ask: can such a system work well under various weather conditions? It was decided to get the answer to this question by the method of mathematical modeling by jointly considering the air regime of all rooms of the building with a ventilation system, which makes it possible to identify a reliable qualitative and quantitative picture of the distribution of air flows in the building and the ventilation system.

For the study, an 11-storey one-entrance building was chosen, in which all apartments have corner ventilation. The last two floors are occupied by duplex apartments. The areas of the windows and their air permeability in the building correspond to the norms, as well as the air permeability of the doors (the air permeability of the windows of the 1st floor was 6 kg/h m 2 , and the air permeability of the doors was 1.5 kg/h m 2). There are windows in the stairwell on all floors. Each apartment has two "trunks" of natural exhaust ventilation systems made of metal. All ventilation systems were accepted as designed by the design organization. The main channels are provided with the same diameter in height. The diameters of the side branches are also made the same. Diaphragms were selected for the side branches, which equalize the exhaust air flow rates across the floors. The height of the shaft above the floor of the upper technical floor rises by 4 m.

The calculation determined the air flow rates that make up the air balance of each apartment at various outside temperatures, wind speeds and with open and closed windows.

In addition to the main option described above, options were considered with apartment doors corresponding to an air permeability of 15 kg / h m 2 at a pressure difference of 10 Pa and with windows providing an air permeability of 10 kg / h m 2 on the ground floor at an outside temperature of -26 ° C .

The calculation results for an apartment with the required exhaust flow rate of 120 m 3 / h m 2 are shown in fig. 4.

Figure 4a shows that with normative windows and doors and closed vents, the flow rates of air removed through the exhaust ventilation are almost equal to the flow rates of infiltration air during the entire heating season in windy and calm conditions. There is practically no air movement through the apartment doors (all doors work for inflow with a flow rate of 0.5 - 3 m 3 / h m 2). Infiltration is observed through the windows of the windward and leeward facades. The costs on the top floor refer to the duplex apartment, which explains the increased costs. It can be seen that the ventilation works fairly evenly, but with the windows closed, the air exchange rates are not met even at an outside air temperature of -26 ° C and a head wind of 4 m / s on one of the facades of the apartment.

On fig. 4b shows the change in air flow rates of the same version of the fences in the building, but with open windows. The doors still isolate the apartments of all floors from the stairwell. At +5°С and calm air exchange of apartments is close to the standard one with a slight overflow on the first floors (curves 3). At an outside air temperature of -26°C and a wind of 4 m/s, air exchange exceeds the standard by 2.5 - 2.9 times. Moreover, the vents of the windward facade (curve 1n) work for inflow, and the side windows - for exhaust (curve 1b). The ventilation system removes air with a large overflow. The same figure shows the air flow rates in the warm period of the year (outside air temperature according to parameters A). The difference between the temperatures of the outdoor and indoor air is 3°C. At a wind speed of 3 m/s, air enters through the windows of one facade (curve 5n), and it is removed through the windows of the other (curve 5b). Air exchange is sufficient. When there is no wind (or with a windy facade), all windows compensate for the exhaust, which is from 35 to 50% of the norm (curves 4).

Figures 4c and 4d illustrate the same modes as figures 4a and 4b, but with doors with increased air permeability. It can be seen that ventilation is still working steadily. When the windows are closed, the flow of air through the apartment doors is insignificant, when open - in the lower floors, the air leaves through the doors to the stairwell, in the upper floors it enters the apartments. On fig. 4d, the air flow through the doors refers to options 1 and 5. In options 3 and 4, the air flow through the doors is negligible.

Variants of windows and doors of increased air permeability with closed windows are shown in fig. 4d. Calculations show that with breathable windows, infiltration ensures the ventilation rate of air only in the coldest period of the year.

Conclusion

In double sided apartments, natural ventilation can work well for most of the year if properly sized and installed. In hot weather, only the effect of wind can provide the required air exchange.

Modern standards of air permeability of windows make you think about special measures to ensure the flow of outside air into apartments.

A significant improvement in the air regime of residential buildings can be achieved if the air permeability of apartment doors is brought closer to the norm. On the one hand, the air permeability rate could even be slightly increased, and on the other hand, it is necessary to give an approach to calculating the required air permeability of apartment doors. Now it is impossible to choose doors that meet the norm for buildings of various heights and layouts, taking into account climatic factors.

Ventilation in a private house or apartment: how to do it right?

Good ventilation does not at all mean the mandatory installation of expensive supply and exhaust systems in a house or apartment: it is enough to properly organize the movement of air flows in a building or room. In this article, we will consider the basic principles of creating an air exchange system in a house, which will ensure the optimal microclimate in the house and the safety of its structures.

What is ventilation and why is it needed?
Ventilation is an organized exchange of air in the premises, which is created to remove excess heat, moisture, harmful and other substances that accumulate in the atmosphere of the premises and to supply fresh air for breathing. With the help of ventilation, a microclimate and air quality are acceptable or optimal for a person. Also, ventilation is needed to protect and ensure the required level of safety of buildings under various natural and man-made impacts and phenomena.
British building codes Building Regulations 2010 Document F, Section 1 define the purpose of home ventilation as follows:
p.4.7 Ventilation is necessary to achieve the following goals:
a. inflow of external air for breathing;
b. dilution and removal of pollutants in the air, including odors;
with. control of excess humidity (created by water vapor contained in indoor air);
d. air supply for fuel-burning equipment.

What are the optimal conditions for a person?

The air characteristics are considered to be optimal, under which physiological comfort is ensured with prolonged and systematic exposure to a person. Most often, optimal conditions mean air temperature from 21 to 25 °C, relative humidity from 40 to 60%, air velocity not more than 0.2-0.3 m/s and gas composition of the air as close as possible to the natural composition of atmospheric air (75 .5% - nitrogen, 23.1% - oxygen, 1.4% - inert gases).

What is ventilation?
Natural ventilation is the most common type of ventilation of premises, which creates air exchange due to the difference in density of warmer air inside the room and colder air outside. This type of ventilation is simple in design and operation.

Forced or mechanical ventilation of premises is provided by mechanical motivation - the use of fans to move air. Mechanical ventilation can be supply, exhaust or supply and exhaust.

Mixed ventilation, in addition to forced ventilation, uses natural ventilation to supply and remove air.

According to the ratio of air supply and removal, supply, exhaust and mixed ventilation can be distinguished.

Advantages and disadvantages of various types of ventilation

Comparison of different types of ventilation

Type of ventilation	Advantages	disadvantages
Exhaust ventilation	Simple and inexpensive design Suitable for local ventilation	Backdraft may occur when using stoves and fireplaces Supply air comes from random sources Heated or cooled air is lost.
Forced ventilation	Does not adversely affect the operation of stoves and fireplaces Excessive back pressure prevents the entry of pollutants from the atmospheric air (for example, radon) Possibility of supplying air to a certain place (for example, to a furnace)	Does not remove polluted air from rooms Air supply with high or low temperature or humidity Feeling of drafts possible
Balanced air exchange system	No air infiltration or exfiltration phenomena Fine adjustment of the balance of air supply and air flow is possible Recovery of thermal energy of exhaust air is possible	Complex design and high cost

What air exchange is recommended for living quarters?
The recommended amount of air exchange is determined based on the number of people sitting in the premises, the area (volume) of the premises and the type of ventilation. For natural ventilation in rooms where there is at least 20 meters of living space per person, it is recommended that the air flow rate be at least 30 cubic meters of air per hour (but not less than 35% of the volume of the entire room). In buildings where there is less than 20 square meters of area per person, air exchange should be at least 3 cubic meters of air per hour for each square meter of living space.

The British Building Code (2010 Part F, Ventilation, tables 5.1-5.2) provides a simplified calculation of the required constant air exchange in a house:

According to the requirements of the International Building Code for Residential Buildings (IRC, Section R303.4), if the level of fresh air infiltration into the house is less than 5 volumes per hour, the installation of mechanical ventilation is required in the house.

How to arrange ventilation in a house or apartment?

Most often, mixed ventilation is arranged in houses and apartments with periodic use of forced exhaust ventilation in places of high humidity and local deterioration of the gas composition of the air (bathrooms, kitchens, saunas, boiler rooms, workshops, garages) in combination with natural supply and exhaust ventilation.

When aerating the premises, the natural flow of air into the premises is carried out when airing through open windows and doors (volley ventilation) and infiltration through cracks and leaks in the enclosing structures, windows. In modern houses with practically no gaps in the building envelope and windows, air is supplied through slotted valves in the upper part of the window frames (wooden or plastic frames), through conventional air infiltration valves installed in the outer walls, or through mechanical infiltrators that provide both passive, as well as the air flow induced by the fan, its cleaning and heating if necessary.

To remove air during channelless ventilation, windows, vents and transoms are used. Air removal occurs either due to the difference in air density inside and outside the building, or due to the pressure difference on the windward and leeward sides of buildings. This type of ventilation is the most imperfect, since the air exchange in this option is the most intense, it is difficult to regulate, which can lead to drafts and a rapid decrease in comfortable indoor air temperature.

A more advanced scheme of natural ventilation is a scheme using vertical exhaust ventilation ducts. Exhaust ducts should be located in the thickness of the inner walls or in attached blocks near the inner walls. To prevent freezing, condensation and deterioration of traction, ventilation ducts passing through cold attic spaces should be well insulated. To enhance the draft, the ventilation ducts on the roof are equipped with deflectors.

Intake openings for the removal of natural exhaust ventilation from the upper areas of the room are placed under the ceiling at least 0.4 meters from the ceiling and at the same time at least 2 m from the floor to the bottom of the openings, so that only superheated (overmoistened, gassed) air is removed from the area above the human growth.

In houses with stoves and fireplaces, separate ventilation ducts are laid to supply outdoor air to heaters, which avoids the troubles associated with insufficient air supply to the combustion zone, the occurrence of reverse draft, a sharp decrease in oxygen concentration, the need to keep windows open when stoves and fireplaces are operating. .

Mechanical exhaust ventilation is added for places where air pollution accumulates (a hood over a gas stove), in places of excessive humidity (bathrooms, saunas, swimming pools), in a kitchen connected to a living room or dining room, in a kitchen without a window. Forced ventilation will also be required at very low outdoor temperatures (below -40°C).

Common errors in the ventilation device in houses and apartments.

1 . The complete absence of a ventilation system. Strange as it may sound, the main mistake of ventilation systems in country houses is the complete absence of ventilation systems. Homeowners, saving on ventilation ducts, hope that it will be possible to ventilate the house through vents or window sashes. However, effective ventilation is not always possible due to natural and temperature conditions, and the air quality inside the house is rapidly deteriorating, humidity is rising, and mold is appearing. Rooms without windows must be ventilated.

2. Lack of devices for air supply to the premises. There are no accidental sources of air infiltration in modern practically hermetic houses with a continuous vapor barrier circuit that excludes slotted air infiltration, with window frames with seals. To ensure ventilation in such houses, it is necessary to install air infiltration valves in the walls or slotted valves in the window frames.

A separate supply duct for outdoor air is required for the normal and safe operation of each stove or fireplace. Moreover, it is necessary to supply air from the street, and not from the underground, where radioactive soil gases can accumulate. If a separate channel for a stove or fireplace is not provided, then it will be necessary to install a mechanical supply ventilation that is constantly working in the room during the heating of the stove.

3. Interior doors without ventilation gaps at the bottom or without ventilation grilles. When organizing natural ventilation, less polluted air moves from sources of infiltration or open windows and doors through all rooms to ducted exhaust ventilation in rooms with more polluted air (kitchens and bathrooms). For free air movement, it is necessary to have ventilation gaps under the doors (S = 80 cm 2) and ventilation grilles on the doors to the bathrooms (S = 200 cm 2) for fresh air inflow.

4. Availability of air communication in apartments of apartment buildings with stairwells or neighboring apartments. Through unsealed channels for the passage of pipes and communications, through socket boxes and keyholes, polluted air from stairwells or neighboring apartments is infiltrated into the apartment instead of fresh atmospheric air.

5. Installation of ventilation ducts in the outer walls, in the junctions with the outer walls, the passage of ventilation ducts through unheated premises without insulation. As a result of cooling or freezing of the ventilation ducts, the draft deteriorates, and condensate forms on the internal surfaces. If the air ducts are located near the outer wall, then an air or insulated gap of at least 50 mm is left between the outer wall and the air duct.

6. Installation of intake grilles for exhaust ventilation ducts below 0.4 m from the ceiling plane. The accumulation of overheated, waterlogged and polluted air under the ceiling.

7. Installation of intake grilles for exhaust ventilation ducts below 2 m from the floor plane. Removal of warm air from a person's comfort zone, lowering the temperature in the comfort zone, creating "drafts".

8. The presence of two or more exhaust ducts in remote places of an apartment or house, horizontal sections of air ducts. The presence of different ventilation ducts remote from each other reduces the ventilation efficiency, as well as the slope of the ventilation ducts at an angle of more than 30 degrees from the vertical. Horizontal sections of air ducts require the installation of additional duct fans.

9. Connecting the hood above the stove to the exhaust duct ventilation in the kitchen with full sealing of the ventilation duct opening. One of the most common mistakes of amateur builders and cobblers. As a result, the exhaust air from the kitchen stops, odors spread throughout the apartment. The connection of the hood must be carried out while maintaining the supply grille of the exhaust duct with a check valve installed to prevent the exhaust air from being drawn back into the kitchen.

10. Removing air from bathrooms through the wall to the street, and not through a vertical ventilation duct. In cold weather, the air may not be removed through the through channel, but rather enter the bathroom. When using an exhaust fan in such a scheme, its blades may freeze over.

11. Common ventilation duct for two adjacent rooms. In this case, the air may not be discharged outside, but mixed between rooms.

12. Common ventilation duct for rooms on different floors. It is possible to throw polluted air from the lower floor to the upper one.

13. Lack of a separate ventilation duct for rooms on the top floor. Leads to deterioration of air quality (increased humidity, temperature, pollution) on the upper floor .

14. Lack of a separate ventilation duct for the premises of the lower floor. As a result, polluted air from the lower floor rises to the upper floor, preventing the inflow of fresh air from the atmosphere.

15. Lack of an exhaust ventilation duct in rooms without windows, behind two doors from the nearest window. Stagnation of air in the room, violation of the flow of air into neighboring rooms.

16. Conclusion of the ventilation duct to the attic, "to make it warmer." A common misconception of self-builders, leading to poor ventilation and moistening of roof structures. A fatal mistake in an unventilated attic.

17. Laying transit air ducts from technical rooms, boiler rooms and garages through living rooms. Possible leakage of polluted air into living quarters.

18. Lack of natural supply and exhaust ventilation in basements. Basements, as places of potentially high humidity and concentration of radioactive soil gases, should receive atmospheric air through the supply air duct and have a separate exhaust duct for natural ventilation. In radon-hazardous areas, exhaust ventilation from basements should have a mechanically driven ventilation duct isolated from the rest.

If the basement has a constant air exchange with the living space through open openings, then the ventilation of the house with the basement is organized as for a multi-storey building.

19. No or insufficient ventilation of cold undergrounds. In the outer walls of basements and technical undergrounds that do not have exhaust ventilation, ventilation should be provided with a total area of ​​at least 1/400 of the floor area of ​​the technical underground, basement, evenly spaced along the perimeter of the outer walls. The area of ​​one vent must be at least 0.05 m 2. In radon-hazardous areas, the total area of ​​ventilation ducts for basement ventilation should be at least 1/100 - 1/150 of the basement area.

20. Absent or insufficient ventilation of steam baths and saunas. To create a healthy atmosphere in steam rooms, air exchange of 5-8 steam room volumes per hour should be organized. Air is supplied to the steam room through a separate supply air duct under the stove or heater. Air is removed from the sauna or bath through an air duct in the opposite corner of the steam room, located under the shelves at a height of 80 to 100 cm. For quick removal of hot, moist air, a blocked exhaust duct is provided with air intake from the steam room ceiling.

21. Missing or insufficient ventilation of the attic space.

In a roof with a cold attic, the interior space must be ventilated with outside air through special openings in the walls, the cross-sectional area of ​​​​which, with a continuous pitched roof, must be at least 1/1000 of the floor area. That is, for an attic with an area of ​​100 m 2, ventilation openings in the attic space with a minimum area of ​​at least 0.1 m 2 are required.

Andrey Dachnik.

Our well-being depends on the efficiency of ventilation. Therefore, each residential building must be equipped with an air exchange system. The ventilation of a residential building is always organized according to the same scheme: clean air is supplied to the rooms, and removed through the supply openings in the kitchen, bathroom and pantry. There are several ways to organize air exchange in a residential building.

Types of ventilation

Natural air exchange system

Ventilation systems come with forced and natural impulses. In natural ventilation systems, air flows are driven by draft, which occurs under the influence of temperature differences, pressure drops and wind load. In forced systems, air exchange is carried out with the help of fans.

Classification of ventilation by purpose:

• Supply - supply air to the room;
• Exhaust - remove exhaust air from the house;
• Supply and exhaust - perform the functions of both supply and exhaust systems.

Supply systems

Forced ventilation

Supply ventilation is designed to supply fresh air into the room using air blowers. Such systems can have a different configuration and cost.

Varieties of devices for supplying air to the house:

• supply valve;
• Supply fan;
• Supply unit.

The valve allows air to flow in a natural way. At the place of installation of the valve, they are window and wall. For window ventilation, they are mounted in the upper part of the plastic window. To install a wall valve, a through hole is drilled in the wall, the optimal location is between the window frame and the battery, so that the incoming air warms up a little in winter.

Fans for air supply are installed in the outer wall or window frame. Such simple devices as valves and fans have a number of disadvantages, namely: weak filters, lack of air heating in winter and cooling in summer. These disadvantages are deprived of type-setting and monoblock installations.

Exhaust systems

Exhaust forced ventilation

Exhaust ventilation provides the removal of air from the room, it can be natural and forced. Removal of air masses naturally occurs through a vertical exhaust pipe, the upper end of which is brought out of the roof. Air ducts from different rooms (kitchen, bathroom, pantry) can be connected to the central exhaust pipe, but only if they are located next to each other. For rooms located in different parts of the house, you need to install separate exhaust pipes.

Important! In order for the system to work effectively, the air ducts should not be placed parallel to the ceiling (allowable angle of 35º), sharp turns should also be avoided.

Exhaust pipe installation rules:

• The traction efficiency depends on the height of the pipe, the upper end of the channel must protrude at least 1 m above the level of the ridge;
• Exhaust pipes should be installed strictly vertically;
• To avoid the formation of condensate, the junction of the pipe to the roof must be carefully sealed using cement mortar or sealant.

If you choose the right model and type of fan, taking into account the purpose and size of the room, the exhaust device will function especially efficiently. Such fans are installed in the kitchen or bathroom. There are devices for mounting in round and rectangular ducts.

Supply and exhaust ventilation

Natural supply and exhaust system

Supply and exhaust ventilation simultaneously performs the functions of a supply and exhaust unit. In systems, special attention should be paid to the installation of the exhaust pipe, as it provides draft, and hence the flow of air into the room. As already mentioned, fresh air flows into the house through gaps in building structures or supply valves. Air exchange in forced supply and exhaust ventilation can be provided in several ways: fans, monoblock or stacked air exchange system.

Type-setting and monoblock installations

Elements of stacked ventilation

Type-setting and monoblock installations, according to the type of action, are divided into supply, exhaust and supply and exhaust devices. Type-setting ventilation consists of a powerful supply fan, filters, air humidifiers, a heater, noise absorbers and air ducts, and ventilation grilles. The placement of stacked ventilation requires a lot of space, usually the main units are installed in a separate room (ventilation chamber) or in the attic. In addition, the unhidden wiring of air channels does not look aesthetically pleasing. Therefore, it is hidden behind suspended structures, which is difficult to do in a room with low ceilings.

Monoblock units are characterized by silent operation and small dimensions. They do not require a special place for installation, they can be attached to the wall in the corridor, loggia. All elements (filter, fan, heat exchanger) are enclosed in a housing made of noise-absorbing material. Monoblocks are suitable for installation in small cottages and apartments.

Air flow

Properly organized air exchange

For any ventilation, both natural and forced, it is important to properly organize the movement of air flows in the room. Air must move freely from the inlet to the exhaust.

Airtight interior doors often interfere with the free movement of air masses. To avoid stagnation, it is recommended to leave a two-centimeter gap between the floor and the door leaf or to insert a special overflow grille.

Recovery systems

Ventilation system with heat recovery

Recuperative ventilation systems are becoming increasingly popular. This is due to the fact that in the cold season a huge amount of energy is spent on heating the room. The heat exchanger allows saving from 40 to 70% of heat due to the heating of the incoming flows with the outgoing, warmer air.

Important! In winter, the recovery is not enough to bring the air temperature to a comfortable level (20º). It is necessary to additionally heat the air flows with heaters built into the system.

The recuperator is a heat exchanger, through the body of which passes the incoming and outgoing from the house. Air masses are separated by thin metal plates through which heat transfer occurs. In summer, the air will be partially cooled in the same way.

Based on the foregoing, we see that it is possible to organize air exchange that is comfortable for a particular room in several ways, and everyone chooses for himself the type of construction that he does not bypass for certain needs or type of structure.

This article will consider the purpose and classification of ventilation systems for residential premises. We will tell you how to calculate the ventilation system and give an example of the calculation of ventilation systems. Consider how to check whether ventilation is working and give a detailed method for calculating ventilation systems.

Classification of ventilation systems

Ventilation systems of residential and public buildings can be classified into three categories: according to their functional purpose, according to the method of inducing air movement and according to the method of air movement.

Types of ventilation systems by function:

1. Supply ventilation system (ventilation system that provides fresh air to the room);
2. Exhaust ventilation system (ventilation system that removes exhaust air from the room);
3. Recirculation ventilation system (ventilation system that provides fresh air to the room with a partial admixture of exhaust air).

Types of ventilation systems according to the method of inducing air movement:

1. With mechanical or artificial (these are ventilation systems in which air is moved using a fan);
2. With natural or natural (air movement is carried out due to the action of gravitational forces).

Types of ventilation systems by way of air movement:

1. Duct (air movement is carried out through a network of air ducts and channels);
2. Channelless (air enters the room in an unorganized manner, through leaky window openings, open windows, doors).

What are the risks of poor ventilation?

If there is insufficient flow in the house, then the room will experience a lack of oxygen, high humidity or dryness (depending on the time of year) and dustiness.

Fogging windows due to insufficient ventilation

If there is insufficient exhaust in the house, then there will be increased humidity, greasy soot on the walls of the kitchen, fogging of windows in the winter, a fungus on the walls, especially the bathroom and toilet, as well as walls covered with wallpaper, is possible.

Fungus on wallpaper with insufficient ventilation

And as a consequence, an increased risk of diseases of the cardiovascular and respiratory systems. In addition, most furniture and finishing materials constantly release hazardous chemical compounds into the air. Their MPC (maximum permissible concentration) in the sanitary and hygienic conclusions for this furniture and finishing materials is set from the conditions of compliance with ventilation standards. And the worse the ventilation works, the more the concentration of these harmful substances in the air at home increases. Therefore, the health of the residents of the house directly depends on ensuring proper ventilation.

How to check if your ventilation is working?

First of all, you can check if the hood is working. To do this, hold a lighter or a piece of paper to the ventilation grill installed in the wall of the bathroom or in the kitchen. If the flame (or a piece of paper) is bent towards the grate, then there is a draft, the hood is working. If not, then the channel is blocked, for example, clogged with leaves through the duct. If you have an apartment, then the neighbors could block it, making redevelopment of the premises. Therefore, your first task is to provide draft in the ventilation duct.

Checking ventilation for draft with a lighter

If there is a draft, but it is not constant, and neighbors live above or below you. In this case, air can flow to you, from neighboring rooms, carrying odors with it. In this situation, it is necessary to equip the hood with a non-return valve or an automatic shutter, which closes when the back draft is drawn.

How to check whether you have a sufficient section of the hood, we will consider further.

Calculation of air exchange. Formula for calculating ventilation

In order to choose the ventilation system we need, we need to know how much air must be supplied or removed from a particular room. In simple words, you need to know the air exchange in a room or in a group of rooms. This will make it clear how to calculate the ventilation system, select the type and model of the fan and calculate the air ducts.

There are many options for how to calculate air exchange, for example, to remove excess heat, to remove moisture, to dilute contaminants to MPC (maximum permissible concentration). All of them require special knowledge, the ability to use tables and diagrams. It should be noted that there are state regulations, such as SanPins, GOSTs, SNiPs and DBNs, which clearly define what ventilation systems should be in certain rooms, what equipment should be used in them and where it should be located. And also, how much air, with what parameters and by what principle should they be supplied and removed. When designing ventilation systems, each engineer carries out calculations in accordance with the above-mentioned standards. To calculate the air exchange in residential premises, we will also be guided by these standards and use the two simplest methods for finding air exchange: by the area of ​​\u200b\u200bthe room, by sanitary and hygienic standards and air exchange by multiplicity.

Calculation by room area

This is the simplest calculation. The calculation of ventilation by area is done on the basis that for residential premises the norms regulate the supply of 3 m 3 / hour of fresh air per 1 m 2 of the area of ​​\u200b\u200bthe room, regardless of the number of people.

Calculation according to sanitary and hygienic standards.

According to sanitary standards for public and administrative buildings, 60 m 3 / hour of fresh air is needed per person permanently staying in the room, and 20 m 3 / hour for one temporary one.

Calculation by multiplicities

In the regulation, namely Table 4 DBN V.2.2-15-2005 Residential buildings there is a table with the given multiplicities for the premises (Table 1), we will use them in this calculation (for Russia, these data are given in SNiP 2.08.01-89* Residential buildings, Appendix 4).

Table 1. Air exchange rates in the premises of residential buildings.

Premises	Estimated temperature in winter, ºС	air exchange requirements
		tributary	Hood
common room, bedroom, office	20	1x	--
Kitchen	18	-	According to the air balance of the apartment, but not less than, m 3 / hour	90
Kitchen-dining room	20	1x
Bathroom	25	-		25
Restroom	20	-		50
Combined bathroom	25	-		50
Swimming pool	25	By calculation
Washing machine room in the apartment	18	-	0.5 times
Dressing room for cleaning and ironing clothes	18	-	1.5x
Vestibule, common corridor, stairwell, entrance hall of the apartment	16	-	-
Premises for staff on duty (concierge / concierge)	18	1x	-
Smoke-free staircase	14	-	-
Elevator machine room	14	-	0.5 times
Garbage chamber	5	-	1x
parking garage	5	-	By calculation
Switchboard	5	-	0.5 times

Air exchange rate- this is a value, the value of which shows how many times within one hour the air in the room is completely replaced by a new one. It directly depends on the specific room (its volume). That is, a single air exchange is when fresh air was supplied to the room for an hour and “exhaust” air was removed in an amount equal to one volume of the room; 0.5 crane air exchange - half the volume of the room. In this table, the last two columns indicate the multiplicity and requirements for air exchange in the premises for air supply and exhaust, respectively. So, the formula for calculating ventilation, including the required amount of air, looks like this:

L=n*V(m 3 / hour), where

n- normalized air exchange rate, hour-1;

V- the volume of the room, m 3.

When we consider air exchange for a group of rooms within the same building (for example, a residential apartment) or for a building as a whole (cottage), they must be considered as a single air volume. This volume must meet the condition ∑ L pr = ∑ L you are t That is, how much air we supply, the same must be removed.

Thus, the sequence of calculation of ventilation by multiplicity next:

1. We consider the volume of each room in the house ( volume=height*length*width).
2. We calculate the volume of air for each room using the formula: L=n*V.

To do this, we first select from table 1 the rate of air exchange for each room. For most rooms, only the supply or only the exhaust is normalized. For some, such as a kitchen-dining room and both. A dash means that air should not be supplied (removed) to this room.
For those rooms for which the minimum air exchange is indicated in the table instead of the value of the air exchange rate (for example, ≥90 m 3 /h for the kitchen), we consider the required air exchange equal to this recommended one. At the very end of the calculation, if the balance equation (∑ L pr and ∑ L vyt) does not converge with us, then we can increase the air exchange values ​​\u200b\u200bfor these rooms to the required figure.

If there is no room in the table, then we consider the air exchange rate for it, given that for residential premises the norms regulate the supply of 3 m 3 /hour of fresh air per 1 m 2 area of ​​the room. Those. we consider the air exchange for such rooms according to the formula:L=S rooms *3.

All values Lround up to 5, i.e. values ​​must be a multiple of 5.

1. Summarizing separately L of those premises L of those premises, for which the drawing is normalized. We get 2 numbers: ∑ L pr and ∑ L vyt.
2. We draw up a balance equation ∑ L pr = ∑ L you are t.

If a ∑ L pr > ∑ L vy, then to increase∑ L vyt up to value ∑ L prwe increase the air exchange values ​​for those rooms for which we took the air exchange equal to the minimum allowable value in paragraph 3.
Let's consider the calculations with examples.

Example 1: Calculation by multiplicities.

There is a house with an area of ​​140 m 2 with premises: a kitchen (s 1 \u003d 20 m 2), a bedroom (s 2 \u003d 24 m 2), an office (s 3 \u003d 16 m 2), a living room (s 4 \u003d 40 m 2), a corridor (s 5 \u003d 8 m 2), bathroom (s 6 \u003d 2 m 2), bathroom (s 7 \u003d 4 m 2), ceiling height h \u003d 3.5 m. It is necessary to draw up an air balance at home.

1. We find the volume of rooms according to the formula V=s n*h, they will be V 1 = 70 m 3, V 2 = 84 m 3, V 3 = 56 m 3, V 4 = 140 m 3, V 5 = 28 m 3, V 6 = 7 m 3, V 7 = 14 m 3 .
2. Now we calculate the required amount of air in multiplicity (formula L=n*V) and write it down in the table, having previously rounded the unit part to five up. When calculating the multiplicity n, we take from table 1, we obtain the following values ​​​​of the required amount of air L:

Table 2. Calculation by multiplicities.

Note: In table 1 there is no position that would regulate the frequency of air exchange in the living room. Therefore, we consider the air exchange rate for it, given that for residential premises the norms regulate the supply of 3 m 3 / hour of fresh air per 1 m 2 of the area of ​​\u200b\u200bthe room. Those. count according to the formula: L=S rooms *3.

Thus, L pr.living room = S living room*3 \u003d 40 * 3 \u003d 120 m 3 / hour.

1. Summarizing separately L those rooms, for which the air flow is normalized, and separately L those rooms, for which the extract is normalized:

∑ L at t \u003d 85 + 60 + 120 \u003d 265 m 3 / hour;
∑ L vyt\u003d 90 + 50 + 25 \u003d 165 m 3 / hour.

4. Let's make the equation of air balance. As we see∑ L int > ∑ L out, so we increase the valueL vytof the room where we took the value of air exchange equal to the minimum allowable. We have all three rooms (kitchen, bathroom, bathroom). Let's increaseL vytfor the kitchen up to valueL kitchen=190. Thus, the total∑ L you t \u003d 265m 3 /hour. Table condition 1(tab. 4 DBN V.2.2-15-2005 Residential buildings ) done: ∑ L pr \u003d ∑ L vyt.

It should be noted that in the bathrooms, bathrooms and kitchens, we organize only an exhaust hood, without an inflow, and in the bedrooms, an office and a living room, only an inflow. This is to prevent the flow of hazards in the form of unpleasant odors into the living quarters. Also, this can be seen from Table 1, in the cells of the inflow opposite these rooms there are dashes.

Example 2. Calculation according to sanitary standards.

The conditions remain the same. Just add the information that 2 people live in the house, and we will calculate according to sanitary standards.

Let me remind you that according to sanitary standards, 60 m 3 / hour of fresh air is needed for one person permanently staying in the room, and 20 m 3 / hour for one temporary one.

Let's get that for the bedroom L2\u003d 2 * 60 \u003d 120 m 3 / hour, for the office we will accept one permanent resident and one temporary L 3\u003d 1 * 60 + 1 * 20 \u003d 80 m 3 / hour. For the living room we accept two permanent residents and two temporary (as a rule, the number of permanent and temporary people is determined by the customer's technical assignment) L 4\u003d 2 * 60 + 2 * 20 \u003d 160 m 3 / hour, we will write the data obtained in the table.

Table 3. Calculation according to sanitary standards.

Composing the equation of air balances ∑ L pr \u003d ∑ L vyt:165<360 м 3 /час, видим, что количество приточного воздуха превышает вытяжной на L\u003d 195 m 3 / hour. Therefore, the amount of exhaust air must be increased by 195 m 3 /h. It can be evenly distributed between the kitchen, bathroom and bathroom, or it can be served in one of these three rooms, such as the kitchen. Those. in the table will change L exhaust kitchen i will make L exhaust kitchen\u003d 285 m 3 / hour. From the bedroom, study and living room, the air will flow into the bathroom, bathroom and kitchen, and from there it will be removed from the apartment by means of exhaust fans (if installed) or natural draft. Such overflow is necessary to prevent the spread of unpleasant odors and moisture. Thus, the air balance equation ∑ L pr = ∑ L you t: 360=360 m 3 /hour - performed.

Example 3. Calculation by the area of ​​​​the room.

We will make this calculation, given that for residential premises the norms regulate the supply of 3 m 3 / hour of fresh air per 1 m 2 of the area of ​​\u200b\u200bthe room. Those. we calculate the air exchange according to the formula: ∑ L= ∑ L pr = ∑ L ex = ∑ S room *3.

∑ L vyt 3\u003d 114 * 3 \u003d 342 m 3 / hour.

Comparison of calculations.

As we can see, the calculation options differ in the amount of air ( ∑ L vyt1\u003d 265 m 3 / hour< ∑ L vyt3\u003d 342 m 3 / hour< ∑ L vyt2\u003d 360 m 3 / hour). All three options are correct according to the rules. However, the first third is simpler and cheaper to implement, and the second is a little more expensive, but creates more comfortable conditions for a person. As a rule, when designing, the choice of calculation option depends on the desire of the customer, more precisely, on his budget.

Selection of the duct section

Now that we have calculated the air exchange, we can choose the ventilation system implementation scheme and calculate the ventilation system ducts.

Two types of rigid air ducts are used in ventilation systems - round and rectangular. In rectangular ducts, to reduce pressure loss and reduce noise, the aspect ratio should not exceed three to one (3:1). When choosing the section of air ducts, one should be guided by the fact that the speed in the main air duct should be up to 5 m/s, and in the branches up to 3 m/s. Calculate the dimensions of the duct section can be determined by the diagram below.

Diagram of the dependence of the cross-section of air ducts on the speed and air flow

In the diagram, the horizontal lines show the airflow value, and the vertical lines show the speed. Oblique lines correspond to the dimensions of the ducts.

We select the section of the branches of the main air duct (which go directly into each room) and the main air duct itself for supplying air with a flow rate L\u003d 360 m 3 / hour.

If the air duct is with natural air extraction, then the normalized air velocity in it should not exceed 1 m/h. If the air duct has a constantly working mechanical air exhaust, then the air velocity in it is higher and should not exceed 3 m/s (for branches) and 5 m/s for the main air duct.

We select the cross section of the duct with a constantly working mechanical air exhaust.

The costs are indicated on the left and right in the diagram, we choose ours (360 m 3 / hour). Further, we move horizontally until the intersection with the vertical line corresponding to the value of 5 m / s (for the maximum air duct). Now, along the line of speed we go down to the intersection with the nearest section line. We got that the section of the main air duct we need is 100x200 mm or Ø150 mm. To select the branch section, we move from a flow rate of 360 m 3 / h in a straight line to the intersection at a speed of 3 m 3 / h. We get a branch section of 160x200 mm or Ø 200 mm.

These diameters will be sufficient when installing only one exhaust duct, for example in the kitchen. If 3 exhaust ventilation ducts are installed in the house, for example, in the kitchen, bathroom and bathroom (rooms with the most polluted air), then we divide the total air flow that needs to be removed by the number of exhaust ducts, i.e. by 3. And already for this figure we select the cross section of the ducts.

According to this schedule, it is rather difficult to select sections for such small costs. We count them in a special program. Therefore, if you need - ask, we will calculate.

Natural air extraction. This diagram is suitable only for the selection of mechanical drawing sections. The natural hood is selected manually or using section selection programs. Again, please ask.

Note: In our example, it was not, but special attention should be paid to the location of the swimming pool when it is in the house. The pool is a room with an excess amount of moisture, and when calculating the necessary air exchange, an individual approach is required. From practice I can say that the consumption is obtained at least eight times. This is a rather high consumption, and if we take into account that the supply air temperature should be 1-2 ° C higher than the water temperature in the pool, then the cost of air heating in winter is very high. Therefore, for indoor swimming pools it is more logical to use dehumidification systems. These systems work according to the following scheme - the dehumidifier takes moist air from the room, passing it through itself, removes moisture from it (by cooling it), then heats it up to a predetermined temperature and feeds it back into the room. Also, there are systems of dehumidification of air with a possibility of admixture of fresh air.

The ventilation scheme is purely individual for each house and depends on the architectural features of the house, on the wishes of the customer, etc. Meanwhile, there are some conditions that must be observed, and they apply to all schemes without exception.

General requirements for ventilation systems

1. Exhaust air is thrown out above the roof. With natural exhaust ventilation, all channels lead above the roof. With mechanical exhaust ventilation - the air duct is also taken out above the roof either inside the building or outside.
2. The intake of fresh air with a mechanical supply ventilation system is carried out using an intake grille. It must be placed at least two meters above ground level.
3. The air movement must be organized in such a way that the air from the premises moves in the direction of the premises with the release of harmful substances (bathroom, bathroom, kitchen).

In this article, we have analyzed what ventilation systems are and how the required air exchange is calculated. This information will help you choose the right ventilation system and provide the most comfortable microclimate for living in your home.

In the Appendix to the article you will find normative documents that describe the issue of Ventilation from a regulatory point of view.