Regular ventilation of residential and public buildings ensures the timely removal of excess heat, moisture and harmful gaseous impurities that accumulate in the air as a result of people and various household processes.
The air of poorly ventilated dwellings and other enclosed spaces, due to changes in the chemical and bacterial composition, physical and other properties, can cause bad influence on the state of health, causing or worsening the course of diseases of the lungs, heart, kidneys, etc. It has been established that prolonged inhalation of such air in combination with unfavorable temperature-humidity and nervous system and general well-being of a person (headache, loss of appetite, decreased performance, etc.). All this indicates the great hygienic importance of ventilation of residential premises, since clean air, according to F.F. Erisman, one of the first aesthetic needs of the human body.
The amount of required exchange room air with the outside depends on the number of people in the room, its cubic capacity and the nature of the work being done. It can be determined on the basis of various indicators, and as one of them, common in sanitary practice when examining residential premises, the content of carbon dioxide is taken. Ventilation should not allow the content of carbon dioxide in the room to exceed 1%o, which is accepted as an acceptable concentration for ordinary residential premises, classrooms, hospital wards, etc.
The cleanliness of the air in the premises is determined by the provision for each person of the necessary volume of air - the so-called air cube - and its regular replacement with outside air. The amount of ventilation air required for this per person per hour is called ventilation volume.
In residential premises, the norm of the air cube is 25-27 m3, the volume of ventilation is 37.7 m3, therefore, in order to completely remove the spoiled air and replace it with clean atmospheric air, it is necessary to ensure approximately 1.5-2-fold exchange of indoor air with outdoor air during I h. Thus, the frequency of air exchange is the main criterion for the intensity of ventilation. It is calculated by dividing the amount of air entering the room for 1 hour by its cubic capacity.
In rooms where hard physical work is done, for example, in sports halls, the indicated size of the air cube and ventilation volume will be insufficient and the air exchange rate will increase, however, within the permissible values that do not cause strong air currents. In children's institutions, the volume of ventilation may be less. It is also differentiated depending on the purpose of individual public buildings (hospitals, schools, etc.).
When rationing the volume of ventilation, sometimes instead of the frequency of air exchange, the amount of supply or exhaust air is indicated per person per hour.
Natural ventilation is the infiltration of outside air through various cracks and leaks in windows, doors, and partly through the pores of building materials in rooms, as well as their ventilation through open windows, vents and other openings arranged to enhance natural air exchange.
In both cases, air exchange occurs due to the difference in temperature between outdoor and indoor air and wind pressure. This exchange is most intense in an open building system, when the buildings are distant from each other and all four of their sides participate in the air exchange, and the rooms are located on two opposite facades, which creates through ventilation.
Air exchange due to infiltration provides only 0.5-0.75-fold air exchange for 1 hour. Since this is not enough, vents and transoms are used that fold at an angle of 45 ° into the room (Fig. 4.5). In this case, cold air enters the room first up, under the ceiling, and then, partially heated, goes down without forming sharp currents and without causing strong cooling of people. Form size
Rice. 4.5. Transom, a - intake of outside air; b - the flow of air into the room.
dots should be at least 1/50 of the floor area. In the cold season, ventilation is more effective with windows that are fully and often opened for 5-10 minutes than with windows that are ajar for a long time. You should not be afraid of a short-term decrease in the temperature in the room, since the walls and furnishings cool slightly during this time and after the ventilation is completed, the air temperature will quickly recover, the main thing is that in this case a more complete change of air will occur.
In multi-storey buildings to enhance natural ventilation during internal walls ah arrange exhaust channels, in the upper part of which there are receiving holes. The channels lead to the attic into the exhaust shaft, from which air enters. This ventilation system works on natural draft due to the pressure difference formed in the ducts due to the temperature difference, which causes the warmer room air to move upwards. In the cold season, a natural draft exhaust system can provide 1.5-2-fold air exchange per hour; in warm season, its efficiency is insignificant due to the small difference in temperature between indoor and outdoor air.
Artificial ventilation. In public buildings designed to accommodate a large number of people, in hospitals, schools, and in production, natural ventilation alone is not enough to ensure the proper sanitary condition of the air. In addition, in hospitals and children's institutions during the cold season, it is not always possible to widely use it due to the danger of the formation of cold air currents. In this regard, mechanical ventilation is arranged, which does not depend on the outside temperature and wind pressure and provides, under certain conditions, heating, cooling and cleaning of the outside air. Ventilation can be local - for one room and central - for the entire building.
For local ventilation, supply or exhaust electric fans are used, which are installed in windows or wall openings. In public buildings, they are designed mainly for short-term action. In classrooms, gyms, fans operate during breaks between classes, and in a number of rooms with polluted air - periodically. In production, they function for a longer time. Most often, local exhaust ventilation is used, which removes spoiled air, and the inflow clean air carried out by entering through the windows and vents. In rooms with high air pollution (kitchens, toilets), only exhaust fans are installed.
However, local ventilation has certain disadvantages. When using the supply system in winter time cold currents of air are formed in the room, the operation of the fan
Rice. 4.6. Scheme of the supply of o-exhaust artificial central ventilation.
the moat is often accompanied by significant noise, they spoil the appearance of the premises. The most modern type of local ventilation are air conditioning units.
Central ventilation is designed for air exchange in the entire building or in its main premises, it operates constantly or for most of the day. Depending on the purpose of the premises, central ventilation can be supply, exhaust or supply and exhaust, combining the supply of clean air with the removal of spoiled.
On fig. 4.6 shows a diagram of the supply and exhaust ventilation. Outside clean air, for example from a garden, is taken with the help of fans, sometimes at a considerable distance from the building, and is directed through the channel to the supply chamber, where it is cleaned of dust, passing through fabric or other filters. In the cold season, the air is heated to 12-14 ° C, in some cases it is humidified and supplied to the premises through channels in the inner walls. The supply ducts end with openings in the upper part of the walls to exclude the direct effect of colder air currents on people, and are covered with gratings. To remove spoiled air, another exhaust network of channels is laid, the openings of which are located in the lower part of the opposite inner wall; the channels lead to the attic into a common collector, from which air is removed to the outside using a fan.
The supply and exhaust ventilation system ensures the predominance of air inflow over the exhaust, which is especially important in operating rooms of hospitals. In showers, toilets, kitchens, as already mentioned, only an exhaust hood is arranged. In order to save money, many buildings also arrange only exhaust ventilation with the expectation that clean air enters through the vents,
From a hygienic point of view, a supply and exhaust ventilation system is more preferable, which provides an influx of clean heated and, if necessary, humidified air, which makes it possible to better maintain a normal temperature and humidity regime in the premises.
At present, a new, more advanced ventilation system has been developed - air conditioning, which allows you to automatically maintain optimal conditions for temperature, humidity, movement and air purity for the required time. For this, central air conditioning units are used, designed to service public buildings (hospitals, schools, etc.), railway cars, and room air conditioners for individual small-sized premises.
On fig. 4.7 is a diagram of an air conditioning unit. The outside air entering the air conditioners is heated or cooled to the required temperature, humidified
Rice. 4.7. Scheme of installation for air conditioning.
I - hole for suction of outside air; 2 - a hole for air to enter the room; 3 - filter; 4 - nozzles; 5 - a pipe supplying air to the nozzles; 6 - pipeline for supplying fresh chilled or heated water to the system; 7 - pump; 8 - electric motor; 9 - humidification chambers.
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 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 costs of ventilation air, the Moscow regional norms MGSN 3.01-96 "Residential buildings" provide for air exchange of 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 ducts from each exhaust grille, which were connected to the exhaust shaft directly or through a collection duct 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 fundamental solution of natural gas systems exhaust ventilation 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 under construction individual projects, exhaust 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 standard projects multi-storey buildings provides for the construction of a "warm attic" with a height of about 1.9 m. Air enters it from several prefabricated vertical channels, which makes the attic a common horizontal section of the ventilation system. Removal of air from the attic space is carried out 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, for middle lane Russian architects try to place apartments in the building in such a way 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.
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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 unorganized inflow are supply devices various designs installed directly in the outer 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.
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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 poor entrance doors, the inflow into them decreases through the windows and increases through 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.
Due to the installation of tight windows in the building, the device is only exhaust system turns out to be ineffective. Therefore, to supply inflow to apartments, they are used as various devices(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.
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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 quite evenly, but at closed windows 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 norms 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 standard. 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.
Why modern housing must have effective ventilation? What does the natural and mechanical ventilation system consist of, how does it function? What system should be organized at home? How to choose and order efficient ventilation? We will answer these questions today.
What can ventilation do?
My home is my castle. Every year buildings become more reliable and economical. No wonder, because developers now have access to innovative energy-saving technologies and new ones with previously unattainable characteristics. Moreover, the market does not stand still: inventors, manufacturers, marketers and sellers are working tirelessly. High-quality waterproofing of structures, multi-layer walls, insulated floors and roofs, hermetic window blocks, efficient heating - all this does not give the slightest chance for precipitation and ground water, city noise, winter cold and summer heat.
Yes, a person has learned very well how to tightly fence himself off from adverse environmental conditions, but at the same time we have lost contact with the outside world, now the natural, natural mechanism of air self-purification has become inaccessible to us. The layman fell into another trap - moisture, carbon dioxide, substances harmful to health and chemical compounds released by the person himself accumulate and concentrate inside the premises, building materials, household items, household chemicals. Even in developed countries, the number of autoimmune and allergic diseases caused by the multiplication of bacteria, fungi, mold and viruses in the home is steadily growing. No less dangerous is the dust, which consists of the smallest particles of soil, plant pollen, kitchen soot, animal hair, scraps of various fibers, skin flakes, and microorganisms. Dust is not necessarily a guest from the street, it is formed even in a tightly closed non-residential apartment. Latest Scientific research showed that in most cases indoor air is many times more toxic and dirtier than outdoor air.
A decrease in the oxygen concentration in the room significantly reduces the level of working capacity, adversely affects the well-being of residents and their health in general.
That is why the issues of providing ventilation and air purification have become incredibly relevant, along with hydro and thermal insulation of buildings. Modern ones should effectively remove stagnant, “exhaust” air, replace it with fresh air from the outside in the required volume, cleaning, heating or cooling it if necessary.
How do air flows in ventilated rooms?
As we have already noted, the composition of the air inside the operated dwelling is not uniform. Moreover, gases, dust, vapors released in the room are constantly moving due to their special properties - density and dispersion (for dust). Depending on whether they are heavier than air or lighter, harmful substances rise or fall, accumulating in certain places. An even greater impact on inner space exerts the movement of convective jets of heated air, for example, from working household appliances or kitchen stove. Convective currents, rising, can drag even relatively heavy substances into the upper zone of the room - carbon dioxide, dust, dense vapors, soot.
Jets of domestic air interact in a special way with each other, as well as with various objects and building structures, because of which clearly defined temperature fields, zones of concentration of harmful substances, flowing streams of various speeds, directions and configurations are formed in the dwelling.
It is obvious that not all rooms are equally polluted and have excessive humidity. Kitchens, toilets, and bathrooms are rightfully considered the most “dangerous”. Precisely because the primary task of artificial air exchange is to remove harmful substances from places with the highest concentration of harmful substances, ventilation ducts with exhaust holes are arranged in the kitchen and bathroom areas.
The inflow is arranged in "clean" rooms. So, stronger than other flows of substances, "long-range" supply jets, moving, involve large masses of exhaust air in motion, and the necessary circulation appears. The main thing is that due to the direction of the air in the direction of the "problem" premises, unwanted substances do not enter the living rooms from the kitchens and bathrooms. That is why in the tables of building codes regarding the requirements for air exchange, the study, bedroom, living room is calculated only for inflow, and the bathroom, toilet and kitchen only for exhaust. Interestingly, in apartments with four or more rooms, it is recommended that the premises furthest from the ventilation ducts of the bathroom be provided with separate ventilation, with their own supply and exhaust.
At the same time, corridors, lobbies, hallways, smoke-free staircases may not have supply or exhaust openings, but only serve for air flow. But this flow must be ensured, only then the ductless ventilation system will function. Interroom doors get in the way of the movement of air flows. Therefore, they are supplied with overflow grilles or a ventilation gap of 20-30 mm is arranged, raising a blank canvas above the floor.
The nature of the movement of air masses depends not only on the technical and construction characteristics of the premises, the concentration and type of harmful substances, and the characteristics of convective flows. An important role here belongs to the mutual arrangement of the air supply and exhaust points, especially for rooms containing both supply and exhaust openings (for example, a kitchen-dining room, a laundry room ...). In ventilation systems of residential premises, the “top-up” scheme is most often used, in some cases - “top-down”, “bottom-down”, “bottom-up”, as well as combined multi-zone, for example, inflow at the top, and two-zone exhaust - at the top and bottom . It depends on the correct choice of the scheme whether the air will be replaced in the required volume, or an annular circulation will form inside the room with the formation of stagnant zones.
How is air exchange calculated?
To design effective system ventilation, it is necessary to find out how much exhaust air should be removed from a room or group of rooms and how much fresh air should be supplied. Based on the data obtained, it will be possible to determine the type of ventilation system, select ventilation equipment, calculate the cross section and configuration of ventilation networks.
It should be said that the parameters of air exchange in residential buildings are strictly regulated by various state regulations. GOSTs, SNiPs, SanPiNs contain comprehensive information not only about the volume of air to be replaced and the principles, parameters of its supply and removal, but also indicate what type of system should be used for certain rooms, what equipment should be used, where to be located. It remains only to competently examine the room for excess heat and moisture, the presence of air pollution.
The tables, diagrams and formulas set out in these documents are created according to different principles, but in the end they give similar numerical indicators of the required air exchange. They can complement each other with a lack of certain information. Calculations of the amount of ventilation air are made on the basis of studies, depending on the hazards emitted in specific rooms and the norms of their maximum permissible concentration. If for some reason the amount of pollution cannot be determined, then the air exchange is calculated by multiplicity, according to sanitary standards per person, by the area of \u200b\u200bthe room.
Multiplicity calculation. SNiP contains a table that indicates how many times the air in a particular room should be replaced with new one in one hour. For "problem" rooms, the minimum allowable volumes of air replacement are given: kitchen - 90 m 3, bathroom - 25 m 3, toilet - 50 m 3. The amount of ventilation air (m 3 / hour) is determined by the formula L \u003d n * V, where n is the value of the multiplicity, and V is the volume of the room. If you need to calculate the air exchange of a group of rooms (apartment, floor of a private cottage ...), then the L values \u200b\u200bof each ventilated room are summarized.
One more important point is that the volume of exhaust air must be equal to the volume of supply air. Then, if we take the sum of the air exchange indicators of the kitchen, bathroom and toilet (for example, the minimum is 90 + 25 + 50 \u003d 165 m 3 / hour), and compare with the total one-time inflow volume of the bedroom, living room, office (for example, it can be 220 m 3 /hour), then we get the air balance equation. In other words, we will need to increase the hood to 220 m 3 / hour. Sometimes the opposite happens - you have to increase the flow.
The calculation by area is the simplest and most understandable. The formula L=S of the room *3 is used here. The point is that for one square meter building and sanitary standards regulate the replacement of at least 3 m 3 of air per hour.
Calculation according to sanitary and hygienic standards is based on the requirement that at least 60 m 3 per hour be replaced per one person who is constantly in the room, “being in a calm state”. For one temporary - 20 m 3.
All the above calculation options are normatively acceptable, moreover, for the same room, their results may differ slightly. Practice shows that for a one-room or two-room apartment(30-60 m 2) the performance of ventilation equipment will require about 200-350 m 3 / hour, for a three-, four-room (70-140 m 2) - from 350 to 500 m 3 / hour. It is better to entrust the calculations of larger groups of premises to professionals.
So, the algorithm is simple: first we calculate the necessary air exchange - then we select the ventilation system.
natural ventilation
How does natural ventilation work?
The natural (natural) ventilation system is characterized by the fact that the replacement of air in a room or group of rooms occurs under the influence of gravitational pressure and wind action on the building.
Usually, indoor air is warmer than outdoor air, it becomes more rarefied, lighter, so it rises and exits through the ventilation ducts to the street. A vacuum appears in the room, and heavier air from the outside through the building envelope penetrates into the dwelling. Under the influence of gravitational force, it tends downward and exerts pressure on the upward flows, displacing the exhaust air. This is how gravitational pressure appears, without which natural ventilation cannot exist. The wind in turn helps this circulation. The greater the temperature difference between indoor and outdoor, the more speed wind, the more air gets inside.
For more than a dozen years, such a system has been used in Soviet-built apartments of the 1930s-1980s, where the inflow was carried out through infiltration, through structures that let in a large amount of air - wooden windows, porous materials of external walls, loosely closing entrance doors. The amount of infiltration in old apartments is the air replacement rate of 0.5-0.75, which depends on the degree of sealing of the cracks. Recall that for living rooms (bedroom, living room, study ...), according to the norms, it is required that at least one air change occurs in one hour. The need to increase air exchange is obvious, which is achieved by ventilation - opening vents, transoms, doors (unorganized ventilation). In fact, this entire system is an exhaust duct with a natural impulse, since no special supply openings were intended. The extract of such ventilation is carried out through vertical ventilation ducts, the entrances to which are located in the kitchen and bathroom.
The force of gravitational pressure, which pushes the air out, largely depends on the distance between the ventilation grills located in the room to the top of the shaft. On the lower floors apartment buildings usually the gravitational pressure is stronger due to the greater height of the vertical channel. If the draft in the ventilation duct of your apartment is weak or the so-called “draught overturning” occurs, then polluted air from neighboring apartments can flow to you. In this case, installing a fan with check valve or gratings with blinds that automatically close when reversed. You can check the traction force by bringing a lit match to the exhaust opening. If the flame does not deviate towards the channel, then it may be clogged, for example with leaves, and cleaning is required.
Natural ventilation may also include short horizontal air ducts, which are removed in certain areas of the room on the walls at least 500 mm from the ceiling or on the ceiling itself. The outlets of the exhaust channels are closed with louvres.
Vertical exhaust ducts for natural ventilation are usually made in the form of shafts made of bricks or special concrete blocks. The minimum allowable size of such channels is 130x130 mm. Between adjacent shafts there should be a partition 130 mm thick. It is allowed to manufacture prefabricated air ducts from non-combustible materials. In the attic, their walls must be insulated, which prevents the formation of condensate. Exhaust ducts are led above the roof, at least 500 mm above the ridge. From above, the exhaust shaft is covered with a deflector - a special nozzle that enhances air draft.
How to improve natural ventilation? Supply valves
Recently, the owners of the old housing stock have been seriously engaged in energy saving. Practically airtight window systems made of PVC or Euro-windows are installed everywhere, the walls are insulated and vapor-insulated. As a result, the infiltration process practically stops, air cannot enter the room, and regular ventilation through the window sashes is too impractical. In this case, the problem of air exchange is solved by installing supply valves.
Supply valves can be integrated into the profile system plastic windows. Very often they are installed on eurowindows. The fact is that the ability of modern wooden windows"breathe" is a little exaggerated, you will not wait for the inflow through them. Therefore, responsible manufacturers always offer to install a valve.
Window valves are installed at the top of the frame, sash or in the form of a valve handle, they are made of aluminum or plastic, they can be of various colors. Window inlet valves can not only be built into new windows, but can also be mounted on already installed window systems, without any dismantling.
There is another way out - this is the installation of a wall supply valve. This device consists of a branch pipe passing through the wall, closed at both ends with gratings. Wall valves can have a chamber with filters and a noise-absorbing labyrinth. The inner grille is usually manually adjusted until fully closed, but options are possible with automation by means of temperature and humidity sensors.
As we have already said, air movement should be directed towards polluted premises (kitchen, toilet, bathroom), therefore, supply valves are installed in living rooms(bedroom, office, living room). Supply valves are placed at the top of the room to provide an effective “top-up” scheme for the mutual arrangement of ventilation openings for most apartments. Practice shows that it is not the best solution, since the circulation of flows is disturbed.
Pros and cons of natural ventilation
Natural ventilation is practically non-existent in modern construction. The reason for this is low air exchange rates, the dependence of its power on natural factors, lack of stability, severe restrictions on the length of air ducts and the cross section of vertical channels.
But it cannot be said that such a system does not have the right to exist. Compared to forced "brothers", natural ventilation is much more economical. After all, there is no need to purchase any equipment and long air ducts, there are no costs for electricity and maintenance. Naturally ventilated rooms are much more comfortable due to the absence of noise and the low speed of the replacement air. Moreover, there is not always a constructive possibility to mount ventilation ducts for mechanical ventilation, and then sheathe them with drywall boxes or false beams, for example, with low ceiling heights.
mechanical ventilation
What is mechanical ventilation?
Forced (mechanical, artificial) ventilation is a system in which the movement of air is carried out with the help of any pressure devices - fans, ejectors, compressors, pumps.
It is modern and very effective method organization of air exchange in the premises of the most different purposes. The performance of mechanical ventilation does not depend on changing weather conditions (air temperature, pressure, wind force). This type of system allows you to replace any amount of air, transport it over a considerable distance, create local ventilation. The air that is supplied to the room can be prepared in a special way - heated, cooled, dehumidified, humidified, purified ...
The disadvantages of mechanical ventilation include high initial costs, energy costs and maintenance costs. It is very difficult to implement duct mechanical ventilation in a residential area without more or less serious repairs.
Types of forced air ventilation
The best indicators of comfort and performance are shown by general exchange supply and exhaust mechanical ventilation. The balance of supply and exhaust air exchange allows you to avoid drafts and forget about the effect of “slamming doors”. It is this system that is most common in new construction.
For certain reasons, either supply or exhaust ventilation is often used. Supply ventilation supplies fresh air to the premises instead of exhaust air, which is removed through building envelopes or passive exhaust ducts. Supply ventilation is structurally one of the most difficult. It consists of the following elements: a fan, a heater, a filter, a silencer, automatic control, an air valve, air ducts, an air intake grill, air distributors.
Depending on how the main components of the system are made, the air handling unit can be monoblock or stacked. The monoblock system is somewhat more expensive, but it has a greater installation readiness, more compact dimensions. It only needs to be fixed in the right place and connected to it with power and a network of channels. A monobloc installation allows you to save a little on commissioning and design.
Often, in addition to filtration, the supply air requires special preparation, so the ventilation unit is equipped with additional equipment, for example, dehumidifying or humidifying. Increasingly popular are energy recovery systems that cool or heat the supply air using electric heaters, water heat exchangers or domestic split air conditioning systems.
Exhaust ventilation is designed to remove air from the premises. Depending on whether the air exchange of the entire dwelling or individual zones is carried out, mechanical exhaust ventilation can be local (for example, an exhaust hood over a stove, a smoking room) or general exchange (a wall fan in a bathroom, toilet, kitchen). Fans of general exhaust ventilation can be placed in through hole walls, in the window opening. Local ventilation is usually used in conjunction with general ventilation.
Artificial ventilation can be performed with the use of ventilation ducts - duct, or without the use of such - ductless. The duct system has a network of air ducts through which air is supplied, transported or removed from certain areas of the room. With a ductless system, air is supplied through the enclosing structures or supply ventilation openings, then it flows through the interior of the room into the zone of exhaust openings with fans. Channelless ventilation is cheaper and easier, but also less efficient.
Whatever the purpose of the room, in practice it is impossible to get by with one type of ventilation system. The choice in each case is determined by the size of the room and its purpose, the type of pollutants (dust, heavy or light gases, moisture, vapors ...) and the nature of their distribution in the total air volume. Important issues and economic feasibility of using a particular system.
What you need to know for the selection of ventilation?
So, your calculations show that natural ventilation will not cope with the tasks set - too much air needs to be removed, there are also questions with the supply, since the walls are insulated, the windows are changed. Artificial ventilation is the solution. It is necessary to invite a representative of the company that installs climate systems, who will help to select the configuration of mechanical ventilation on site.
In general, the design and implementation of ventilation is best done at the construction stage of a cottage or overhaul apartments. Then it is possible to painlessly solve many design problems, for example, installing a ventilation chamber, installing equipment, distributing ventilation ducts and hiding them suspended ceilings. It is important that the ventilation system has a minimum of intersection points with other communications, such as a heating and water supply system, electrical networks, low-current cables. Therefore, if you are renovating or building, to search for common technical solutions it is necessary to invite representatives of the contractor to the facility - installers, electricians, plumbers, engineers.
The result of joint work depends on the correct setting of tasks. Experts will ask "tricky" questions that you need to answer. The following will be important:
- The number of people in the room.
- Floor plan. It is necessary to draw up a detailed layout of rooms indicating their purpose, especially if redevelopment is possible.
- Wall thickness and material. glazing features.
- Type and height of ceilings. The size of the interceiling space for suspended, hemming, tension systems. Possibility of mounting false beams.
- Arrangement of furniture and heat-producing household appliances.
- Power and location of lighting and heating devices.
- Availability, type and condition of ventilation shafts.
- Features and performance of infiltration, natural ventilation.
- The presence of local exhaust ventilation - wardrobe, umbrella.
- Desired configuration of the supply system - type-setting or monoblock.
- The need for soundproofing.
- Whether or not supply air preparation is required.
- Type of distributors - adjustable or non-adjustable grilles, diffusers.
- Places of installation of distributors of air - a wall or a ceiling.
- The nature of the system control - keys, shield, remote control, computer, smart home.
Based on the data obtained, equipment of a certain capacity, ventilation network parameters, and installation methods will be selected. If the customer is satisfied with the presented developments, the contractor provides him with a working draft of the ventilation system and proceeds with the installation. All we have to do is pay the bills and enjoy clean air.
Turishchev Anton, rmnt.ru
To ensure the normal living of residents in apartment building it is important to correctly calculate and equip its air exchange. That is why the ventilation system in an apartment building is one of the important engineering decisions made at the stage of drawing up project documentation. People's health, comfort and coziness, durability of building structures depend on the quality of its work.
The value of ventilation for a multi-storey residential building
Ventilation in a high-rise building is a vertical structure originating in the basement
Ventilation in high-rise buildings means engineering system. It begins in the basement of a residential building, ends above the surface of the roof. Any attempts to change the design of the shafts, carry out redevelopment, dismantle the ventilation elements on the part of the residents are fraught with a violation of its functionality.
The main task of any type of air exchange is to create normal conditions for life and work. With properly organized circulation, air flows from the rooms towards the exhaust devices in the kitchen and in the toilet. In this way, exhaust air saturated with water vapor, gases, and odors is removed from the apartments.
It should be understood that in a 9-storey building, the speed of air movement through the ventilation duct will differ from the same, but five-story building. That is why an individual calculation of the ventilation parameters for each residential building is carried out: the air velocity in all apartments must be sufficient, regardless of the number of storeys.
Attention! If ventilation in a multi-storey building is forced, then for silent operation exhaust systems soundproofing is provided. Correction of incoming air with the help of dampers, valves will save energy costs for its heating.
Ventilation system design options
Three unified variants of schemes have been developed, which are used depending on the characteristics of air exchange.
- The natural ventilation scheme in a multi-storey building involves the replacement of exhaust flows with fresh air using the natural draft method. It is created by a pressure drop in the exhaust ducts.
- The combined method is based on the forced air supply and the removal of exhaust air in a natural way. Or the inflow is carried out through the windows, slots, holes, and mechanical exhaust ventilation removes it from the room with the help of fans.
- Forced system only. Supply ventilation and removal of the air flow is carried out by mechanical devices. It is of two types: autonomous and centralized. In the first case, air exchange is ensured by the operation of an exhaust fan at the inlet to the air duct, mounted on the facade of the house. Air can also enter through the supply valves. Modern "know-how" - heating (or cooling) of air directly entering the apartment through a heat exchanger installed here.
The centralized principle of operation allows air to be supplied and removed by a common ventilation chamber located on the roof of the house with supply and exhaust ventilation units. Moreover, air circulation occurs constantly, regardless of weather conditions and seasons.
Natural type air exchange: principle of operation
Using the example of panel houses built in the last century, you can see how natural ventilation works in an apartment building. It belongs to the budget option, unlike elite buildings, where modern standards apply, new technologies are used, and energy-saving materials are used.
The device of the ventilation duct in the old house - "Stalin"
A natural type of ventilation can also be found in a brick house of an old housing stock, where air enters through the slots of the porches of wooden windows and doors, and the exhaust is carried out by draft inside a vertical channel, with access above the roof or into the attic. Blocking the supply duct is fraught with a cessation of air exchange throughout the apartment. The insertion of special valves into window structures, overflow gratings in the door solves the problem of uninterrupted operation of natural ventilation.
The ventilation device in an apartment building with separate exhaust ducts for the kitchen, bath and toilet is one of the ventilation schemes. Here, from the listed rooms of each floor, a separate shaft goes to the roof. With its tightness, odors do not flow from neighboring apartments.
Another air exchange scheme includes vertical channels of all apartments, united by outlet ends in one longitudinal manifold. It is located in the attic, and already through the collector the air enters in an organized way into the street. To eliminate pressure losses in the air ducts and increase the draft, the joints are sealed, and pipes are put on the outlet ends of the channels: it is enough to add only 1 m of a pipe segment and orient it at an angle to the common exhaust shaft.
The least efficient, but also viable method is to collect the exhaust air from each apartment into a vertically installed air duct. The efficiency of the system is low, as odors flow from the premises of one apartment to another.
The most optimal and efficient ventilation systems (forced) are currently used in modern houses, where air is forced in and out mechanically. The peculiarity of air exchange here is the use of energy-saving installations - recuperators. As a rule, the fresh air blowing device is located in the basement or technical floor. Additionally, the air is cleaned through a filter system, heated or, conversely, cooled and only then distributed to all apartments. At the upper level (roof), a ventilation unit of identical performance is installed, which completely removes all air pollution.
Attention! The presence of recuperators allows you to heat (cool) the air on the supply of energy taken from the air leaving the apartments.
Assessing different types ventilation, it should be noted that natural air exchange is not very efficient, but it also clogs the ventilation shaft least of all. If there is no construction debris in the channel, then it is enough to clean it once every few years.
Basement and cellar ventilation
Basements are considered an important element of the whole ventilation system. The central shafts originate in the basement space. Usually the type of air exchange here is natural. Raw air is removed through common channels. On each floor and in each apartment, it enters through special openings.
For a constant supply of fresh flow in the socle machines just above the ground (at a height of 0.2 m), air ducts (0.05-0.85 sq.m.) are evenly arranged around the entire perimeter of the base of the house. according to the size of the house. The total area of such holes should be 1/400 of the area of the residential building. These are vented holes. It is impossible to force them or plant green spaces near the foundation.
The ventilation scheme in a residential building will be effective in case of normal operation of all its autonomous links. Any unprofessional or intentional intervention in the ventilation provision of apartments is administratively punishable.
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:
but. inflow of external air for breathing;
b. dilution and removal of pollutants in the air, including odors;
from. 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 various kinds ventilation
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Exhaust ventilation |
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Forced ventilation |
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Balanced air exchange system |
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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 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 and stimulated fan air supply, 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 draft, 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 (exhaust over 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 an complete absence 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 air ducts are located at outer wall, then between outer wall and an air duct leave an air or insulated gap of at least 50 mm.
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 of transit air ducts from technical premises, 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 potential high humidity and concentrations 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 be isolated from the rest ventilation duct with mechanical motivation.
If the basement has 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. Air vents should be provided in the outer walls of basements and technical undergrounds that do not have exhaust ventilation. with total area 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-prone 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.
