Description:

The book reveals basic principles designing ventilation systems for multi-storey buildings, it presents methods for determining the required air exchange in rooms and calculations of air infiltration through leaks in fences, provides a description and assessment of multi-storey ventilation systems residential buildings, technical, economic and performance indicators these systems.

Features of ventilation of high-rise residential buildings

The report was based on materials from the book by I. F. Livchak “Ventilation of Multi-Story Residential Buildings,” which was published in 1951 by the State Publishing House of Architecture and Urban Planning.

The book reveals the basic principles of designing ventilation systems for multi-story buildings, it presents methods for determining the required air exchange in rooms and calculations of air infiltration through leaks in fences, describes and evaluates the ventilation systems of multi-story residential buildings, and provides technical, economic and operational indicators of these systems.

Despite the fact that the book was published in 1951, it remains relevant to this day - because today issues related to the quality of indoor air and the comfortable parameters of the microclimate of buildings and premises are of particular importance.

In this issue of the magazine we publish one of the chapters of this book - “Features of ventilation of high-rise residential buildings,” which was written by I. F. Livchak together with engineer T. A. Melik-Arkelyan.

High-rise buildings include houses above 15 floors, which, as a rule, have technical floors that divide the building in height into zones up to 10–12 floors high.

Technical floors have hermetic ceilings and partitions with hermetic doors on the staircase, preventing the flow of air from the floors of the underlying zone to the floors of the upper zone.

The high height of the building and its planning and operational features have a significant impact on the operation of ventilation. The main factors that must be taken into account when designing high-rise residential buildings include the following:

1. The possibility of increased air flow in winter from the lower floors to the upper ones due to the high height of the building and the influence of zones located above each other. This position creates increased infiltration of outside air into the lower floors of the zone.

2. Increased wind speeds at higher altitudes from the ground. This creates increased infiltration of outside air in windward rooms upper floors.

3. Increased gravitational pressures in the ventilation system due to the high height of the building, reaching up to 20 mm of water in 30-story buildings. Art. at t n = -15 °C and falling to 7 mm water. Art. at t n = 5 °C versus 5–2 mm water. Art. in multi-storey buildings of mass construction.

The magnitude of the available pressures makes it possible to use them as a good stimulator for traction at low outside temperatures. At the same time, significant fluctuations in pressure can create significant unevenness in the operation of ventilation.

4. A significant length of air ducts and, as a result, large hydraulic losses in them, which causes a decrease in the efficiency of deflectors in exhaust shafts.

5. The impossibility of ventilating sanitary facilities in the summer due to the lack of windows in them, as a rule.

To the noted factors it should be added that high-rise buildings, unlike ordinary mass-produced buildings, are equipped with complex engineering equipment: vacuum cleaners, their own telephone exchanges, garbage disposal, elevator facilities, plumbing and heating pumping units etc.

It's complicated engineering equipment necessitates the maintenance of technically qualified operating personnel, who can also be used in the operation of ventilation systems of a residential building.

Therefore, for the buildings under consideration, mechanical ventilation is quite possible.

1. Selection of ventilation system

Sanitary facilities

The impossibility of ventilating sanitary facilities through windows and the ineffective operation of deflectors lead to the need to install mechanically driven exhaust ventilation in sanitary facilities of high-rise buildings, because otherwise for a long period, at outside temperatures of 10–15 °C and above, when gravitational there is no pressure, these rooms will remain without ventilation.

For example, in Moscow, the average number of days with temperatures above 15 °C, according to long-term climatological observations, is 75.72; they occur mainly in May, June, July, August, September and partly October. (In April, only 0.3 days have temperatures above 15 °C, and in October - 3.5 days.)

Kitchens ventilated by a common ventilation system with sanitary units are the main source of the formation of harmful emissions. These emissions, when opening kitchen windows located on the windward side, can spread into the living rooms. Therefore, kitchens should also be equipped with mechanical ventilation.

Ventilating the kitchen and sanitary facilities with common exhaust systems will only simplify the ventilation system of the building as a whole.

Mechanical drive in exhaust ventilation will make it possible to design ventilation systems with increased resistance to air passage, which will reduce bad influence changes in gravitational pressure.

So, for example, considering the productivity ventilation system proportional to the square root of the effective pressure and design resistance systems 30 mm water. Art., we get an increase in productivity for a 30-story building when the outside temperature changes from +5 to –5 °C in

	30+20	=1.15 times
	30+7

If the calculation were carried out only for natural impulse at an outside temperature of 5 °C, then the corresponding increase in system performance would be

	20	=1.7 times
	7

Such an increase in productivity (if the pressure is not regulated by throttling) would lead to excessive air exchange in the rooms, excessive fuel consumption or overcooling of the premises.

Significant resistance exhaust system Mechanical ventilation will also help reduce excess infiltration in windward rooms. With little resistance in the system, the outside air infiltrating into the rooms will flow relatively freely into the exhaust ventilation, as a result of which the pressure inside the room will drop, and the pressure difference on both sides of the windward window will increase, which in turn will increase the infiltration of outside air.

Such a system will be most effective in windward apartments without cross ventilation, located at high altitudes, at high wind speeds.

Thus, the need for mechanically driven exhaust ventilation from kitchens and sanitary facilities is quite obvious.

Living rooms

When analyzing the operation of ventilation devices in mass-construction houses, the presence of natural exhaust ventilation only from sanitary facilities (in the absence of such in living rooms) was considered insufficient.

If there is a guaranteed mechanical impulse on the exhaust from the sanitary units, a fan that develops a sufficiently high pressure can create the necessary vacuum in the apartment, suck in outside air through the cracks of the window openings and thus provide the required ventilation air exchange in the living rooms.

However, with such a system, blowing from windows is inevitable, especially at low outside temperatures.

In addition, the lack of special ventilation devices in living rooms can lead to disruption of normal temperature conditions.

Rooms with more breathable window sashes will increase air exchange at the expense of reduced air exchange in rooms with less breathable sashes.

Thus, stable air conditions in living rooms cannot be ensured, and they will depend on many random reasons. Therefore, you should not leave living rooms in high-rise buildings without special ventilation devices for inflow.

The simplest ventilation device for an organized flow of air into living rooms is the installation of firecrackers in the outer walls under the ceiling of the room. However, this does not exclude blowing in the room, and, in addition, the holes of the “firecrackers” coming out of each room onto the outer surface of the wall will spoil the facade of the building.

A more advanced device is the so-called window sill device, shown in Fig. 1 and 2.

Here, the air intake is carried out through a gap under the metal fender of the window opening, 2.5 cm high. Such a gap is completely invisible from the outside.

The air passes over the heating device through a box 3 made of thin stainless steel measuring 60 x 2.5 cm; at the end of the box, the air hits the vertical wall of the movable valve 2 and exits into the room in the direction from top to bottom. When entering the room, the supply air mixes with the currents of rising warm air from the heating device, as a result of which the blast is significantly reduced.

The advantage of the supply window sill device is the ability to regulate the amount supply air, achieved by changing the width of the gap through which air enters the room. The gap is adjusted by a valve that moves in one direction or another when adjusting screw 1 in rack 4 is rotated.

In Fig. 3 shows another device for a decentralized flow of outside air into a room with heating by a heating device.

Air intake is also carried out under the metal window visor. Next, the air is directed downwards, here it mixes with the air in the room, rises up, touching the radiator, heats up and goes out into the room.

In Fig. Figure 4 shows the possible positions of the control valve, with the help of which (if necessary) you can regulate the degree of heating of the incoming air.

The supply window sill device is much simpler than the device discussed above for supplying air with its heating heating device(Fig. 3).

The weak point of the latter is the narrow valve through which the air flows down. Dampness may form in it; In addition, this channel will become clogged over time, and cleaning it turns out to be impossible.

Cleaning the window sill supply unit (Fig. 2) from dust does not cause any particular difficulties.

All considered options for decentralized inflow have general disadvantages: in them, supply air enters the premises without the necessary purification. Cleaning is needed even for the upper floors, because in large industrial centers, even at high altitudes, the outside air, especially in winter period, turns out to be quite dusty.

The second disadvantage of decentralized inflow is the unevenness of its operation due to the action of wind.

Excessive pressure and vacuum arising under the influence of wind at the outer surface of the building and, consequently, at the intake openings air supply devices, will increase and decrease the amount of supply air.

To reduce the effect of wind speed, special canopies are installed on the outside of the ventilation holes. However, this measure does not bring significant results, since the ventilation hole remains unprotected from the static pressure generated by the wind.

Unevenness of air flow can be significantly reduced by increasing the resistance to air passage in the hole.

So, if the resistance of the inlet opening is taken equal to 0.5 mm water. Art., then extra pressure on the outer surface about 0.25 mm water. Art., formed, for example, by a wind speed of 3 m/s with an aerodynamic coefficient of 0.5, will increase the amount of supply air through the hole in

	0,5+0,25	=1.15 times
	0,5

Thus, in a room where there is a decentralized inflow, a vacuum of about 0.5 mm of water should be maintained. Art., which is usually achieved by exhaust ventilation. Exhaust ventilation and the device for decentralized inflow must be adjusted to this value.

Operating a decentralized air supply device with a higher resistance is undesirable, since this causes an increase in vacuum in the apartment, which leads to significant unorganized air leaks through the cracks of the windows.

It is appropriate to note here that in order to ensure the suction of fresh air through window sill cracks in living rooms, in buildings equipped with exhaust ventilation and decentralized inflow, it is necessary to achieve the greatest possible sealing of windows, especially in kitchens.

A centralized supply system is more advanced, because it is free from the indicated disadvantages of a decentralized air supply to living rooms. It is centralized supply ventilation with mechanical drive that should be recommended for living rooms in high-rise buildings, although the construction of such a system is more expensive than the installation of decentralized supply.

Mechanical urge in supply ventilation makes it possible to provide centralized cleaning of outside air in the supply chamber.

Increased resistance of the supply ventilation system, possible due to mechanical stimulation, will reduce the adjustment required when there is a variable temperature difference between the outside and internal air.

It is possible to equip living rooms with supply and exhaust ventilation, providing each room with supply and exhaust from centralized supply and exhaust systems. However, such a solution cannot be considered economically feasible, since it, in addition to a significant increase in one-time costs for the construction of ventilation and its complication, will also increase operating costs due to an increase (approximately doubling) in the total air exchange in the apartment.

2. Calculation features

The amount of fresh air entering the premises of high-rise residential buildings with the same population density should be the same as in residential buildings of mass construction. However, the infiltration of fresh air, due to increased wind speed at high altitudes and the influence of zones located one above the other, is different in high-rise buildings.

The intensity of infiltration depends on the wind, temperature difference, the tightness of enclosing structures and many other factors, and for each building, depending on its planning features, the intensity of infiltration will be different.

According to approximate calculations made by the authors, for three- to four-room apartments without cross ventilation, equipped with supply and exhaust ventilation and double apartment doors, in a 30-story building divided into three equal zones, outside air infiltration at an outside temperature of -5 °C and average speeds wind is expressed by the following average values:

First zone (up to 40 m from the ground): wind speed 2–3 m/s; the average exchange rate created by infiltrating outside air is 0.25, with an increase in the lower floors to 0.3 and a decrease in the upper floors to 0.2 rpm.

Second zone (40–80 m): wind speed 3–4 m/s; the average exchange rate is 0.35 rpm/h, with an increase in the lower ones to 0.4 and a decrease in the upper ones to 0.3 rpm/h.

Third zone (80–120 m): wind speed 4–5 m/s; the average exchange rate is 0.45 rpm, with an increase in the lower floors to 0.5, and in the upper floors to 0.4 rpm.

The frequency of air exchanges in living rooms created by supply and exhaust ventilation (given the above data) should be as follows:

In the first zone:

On the lower floors:

1.25 – 0.3 = 0.95 rpm;

On the upper floors:

1.25 – 0.2 = 1.05 rpm.

In the second zone:

On the lower floors:

1.25 – 0.4 = 0.85 rpm;

On the upper floors:

1.25 – 0.3 = 0.95 rpm.

In the third zone:

On the lower floors:

1.25 – 0.5 = 0.75 rpm;

On the upper floors:

1.25 – 0.4 = 0.85 rpm.

In all intermediate floors of each zone, the exchange rate can be determined by interpolation, rounded to 0.05 rpm/h. Thus, the air exchange value for living rooms of a multi-story high-rise building is determined within the range of 0.75–1 rpm, which is recommended by temporary technical conditions.

The frequency of exchange in kitchens and sanitary facilities should be the same as in residential buildings of mass construction. The amount of air extracted and supplied to the apartment should be the same.

The initial value for determining the cross-section of the supply and exhaust ventilation channels in high-rise buildings should be considered the speed of air movement, which is taken in such a way that if the fan is inactive, the system can work on natural impulse. For these reasons, it is advisable to have a radius of action of the ventilation system of no more than 10–12 m.

To increase the resistance of the ventilation system during normal operation with an active fan, a damper or throttle valve should be installed on each supply and exhaust duct. These control devices are installed in close proximity to the ventilation grille or at the junction of a group of ducts.

The selection of supply and exhaust ventilation fans is made by pressure depending on the height of the building: for 20 floors, at least 20 mm of water. Art., with 30 floors in at least 30 mm of water. Art. etc.

Otherwise, the calculation of ventilation devices has no special features and is carried out in the usual way.

3. Design of the system

To reduce the number of ventilation chambers in high-rise buildings, it is allowed to connect apartments located in different zones to one chamber.

For natural ventilation to operate, the supply chamber is located below, and the exhaust chamber is located above the serviced premises. Ventilation chambers can be located in the basement, technical floors and attics. In order to prevent draft overturning when the system operates on natural impulse, the ejection of air from exhaust systems serving interconnected rooms must be at the same level.

The installation of independent ventilation ducts from the chamber to the ventilated room in high-rise buildings with a large number of floors causes serious difficulties. Therefore, the following combinations of supply and exhaust ducts are allowed:

a) serving living rooms - in one horizontal channel within one apartment;

b) serving bathrooms and toilets - in one horizontal channel within one apartment;

c) vertical channels - into one collection channel within one zone.

It is also allowed to combine vertical exhaust ducts from homogeneous rooms within the zone into one duct with a break through two floors, as is schematically shown in the section of the building shown in Fig. 5. Such a merger can be allowed in exceptional cases, because when unfavorable conditions Air flow may occur from one apartment to another. In any case, such a combination of channels serving rooms facing opposite sides should not be allowed.

It is recommended to place vertical supply and exhaust ducts mainly in walls or in special shafts made of fireproof materials.

As materials for air ducts, it is allowed to use slag concrete - for channels of large cross-sections and gypsum - for dry air in a dry place; asbestos-cement channels are allowed provided they are protected from destruction in a fire.

The use of metal air ducts is not recommended. In Fig. 6, 7 shows an example of a solution for supply and exhaust ventilation of 48 apartments located between two staircases 24- storey building, divided into three zones.

Heating of the supply air, carried out in the supply chamber, can be done with a plate heater or a heater made of smooth radiators or pipes. A plate heater is more compact than a heater made from smooth radiators or pipes, but its resistance is much greater, which eliminates the possibility of heating the air when the fan is inactive, when the ventilation system operates on natural impulse.

The heaters should be installed in such a way that the entire surface can be cleaned of dust.

Air is purified from dust using oil paper or fabric filters. The former, which are more difficult to operate, provide better cleaning than the latter, which are easier to operate.

It should be noted that the air resistance when passing through the filters reaches 10 mm of water. Art., which excludes the possibility normal operation system when the fan is inactive.

If outside air is taken in for ventilation at a height of more than 50 m, then special cleaning of it from dust is not necessary.

The channel layout of both the supply and exhaust ventilation systems must provide for the possibility of air passing, in addition to the fan, through a bypass valve, so that if the fan is inactive (an accident or a temporary break), the system can operate on natural impulse.

To reduce noise, it is recommended to install fans with a motor on the same axis, and if this is not possible, on a textural transmission. The peripheral speed of the centrifugal fan wheel should not exceed 18 m/s when installed in the basement and 15 m/s when installed on technical floors.

In addition to the above restrictions, to prevent noise transmission, it is recommended to install an independent foundation under the fan and motor, not connected to the walls of the building, install sound and vibration insulating gaskets between the foundation and the fan, and connect the fans to air ducts using elastic pipes. To eliminate the transmission of sound through the air duct, sound silencers are installed in the air ducts.

For easier maintenance large number located in different places ventilation units It is recommended to concentrate push-button starters of all electric fans in one control center. There, it is necessary to include devices in the electrical circuit to control the operation of the fans.

It is advisable to have instruments in the control center that indicate the temperature and humidity of the supply air entering the chambers.

To inspect and clean ventilation ducts, it is recommended to install special inspection hatches in them.

It is most advisable to locate hatches in the technical floor, in the attic or in the lower floor, at the point where the vertical ducts join the common prefabricated air duct.

Installation adjustment valves are installed on the vertical ducts at the point where they are connected to the prefabricated air duct.

The laying of ventilation ducts and the installation of supply exhaust grilles in high-rise residential buildings is carried out in the same way as for residential buildings of mass construction.

Air quality in residential premises has a direct impact on the health and well-being of its inhabitants. Therefore, much attention is paid to the development of supply ventilation in a nine-story panel building and any other complex. Calculation and design of the scheme is carried out at the stage of drawing up the project.

Procedure for working on the project

The design engineer must think over the location of the air ducts, calculate their dimensions and main technical specifications. The work is carried out taking into account external pollution and noise, the category and number of floors of the building. In addition, it is determined:

• ventilation line power;
• system power consumption;
• dimensions main functional units, etc.

When drawing up drawings, they are guided by GOST requirements and rules fire safety. For example, the use of non-combustible materials and the installation of special valves can prevent the spread of fire through air ducts during a fire. Residential ventilation system panel house should also help maintain a comfortable indoor microclimate. Penetration of cold air currents into apartments is not allowed.

System design features

Most houses built during the Soviet period have a ventilation system, the operation of which depends on the strength of the wind and the frequency of opening windows and doors. Fresh air penetrates inside the apartment and displaces stale masses into ventilation ducts.

Openings were provided in the kitchen, bathroom, toilet and were connected into a common shaft. In order for the air to change, the windows had to be opened regularly. Such ventilation in panel house called mixing. Here are some features of this system:

1. The layout of the air ducts can be changed. Engineers have developed a more efficient distribution, in which ventilation ducts from apartments do not go directly into the common collector, but form booster shafts. The air ducts are connected to the main pipeline through the floor, and the exits from the last and penultimate floors lead directly to the street.
2. Air exchange with mixing is essentially a draft that provides an influx of fresh air. The system is effective for rooms with good vapor barrier, concrete or brick walls. In other cases, constant drafts will cause discomfort to residents.

With the advent of new energy-saving technologies and the widespread installation of sealed doors and windows, the air exchange system with mixing has lost its relevance. She simply stopped coping with her main task. The number of stagnant zones in apartments has increased, the quality of life has decreased.

Supply and exhaust circuits appeared. They allow you to organize sufficient air exchange, while maintaining heat and without forcing residents to constantly ventilate the premises. System Features:

1. Special supply valves in the air ducts allow you to regulate the speed of movement of air masses. Thus, it is possible to control the temperature and humidity conditions in the room.
2. Installing fans allows you to slightly increase the cross-section of the air ducts and reduce the noise of the system.
3. Keeping heat indoors has reduced heating costs in the winter. For residents of the northern regions, this is a significant saving.

Improving ventilation schemes in a panel house had a positive impact not only on people’s quality of life, but also extended life finishing materials, building structures. Reducing air humidity prevents the appearance of fungi and mold on the walls. Corrosion of metal elements is also slowed down.

Ventilation system selection

The ventilation device in a panel house is made according to one of three types:

1. Natural. The change in flows occurs due to the difference in temperature, pressure of external and internal air. Draft occurs in ventilation ducts, “sucking” stagnant masses out of the room. The flow of fresh air comes from windows and doors. This system is recommended for multi-storey buildings located inside the block. At the same time, the level of external noise generated by street transport should not exceed 50 dBA.
2. Forced. Air masses move under the influence of special technical equipment. Both inflow and exhaust are carried out mechanically.
3. Combined. In such systems, either inflow or exhaust are mechanized, depending on the requirements. Combined drive ventilation is optimal for houses where the external noise level exceeds 50 dBA.

None of the systems is universal. The choice is made by the designer for each specific building.

Installation of supply and exhaust air ducts

Rules for installing supply systems for residential premises:

1. If there is no heat exchanger in the duct, and the air is supplied cold to the apartment, then the air duct exit is located at the top of the wall. This makes it possible to mix the flows and optimize their temperature.
2. If heating devices are installed indoors, then the supply ventilation outlet is located behind them or immediately above the heaters.
3. If heat exchangers or other heating mechanisms are installed in the air ducts, then the inflow can be located in any convenient place, both below and above.

Diversion shafts are always installed under the ceiling, at a height of at least 2 meters above the floor. This arrangement contributes effective removal exhaust air.

If the ventilation of a 9-story panel building or any other apartment building is disrupted, residents do not have the right to carry out any manipulations on their own. It is only allowed to clean the channel at arm's length from the wall. In other words, you can remove the grate and vacuum the shaft, but in case of serious damage, you should immediately call a specialist.

The phrase “struggle for quality of life” is perceived by most of us as synonymous with the concept of “striving for material wealth.” Meanwhile, the air quality in a residential area is much more important than “status” interior elements, branded clothing or designer furniture. After all, long-term and systematic exposure to low-quality (inappropriate) acceptable standards) air can cause deterioration in well-being, decreased performance and, alas, deterioration in health. It is not for nothing that the permissible and optimal standards for air mobility, its temperature, and humidity are prescribed in technical regulations and codes of practice. According to the requirements of GOSTs, taking into account all the parameters of the room, a ventilation scheme is being developed in a panel house, brick high-rise building, any other apartment building. To ensure the necessary air exchange (removal of polluted air and influx of fresh air), a ventilation system is calculated and designed. Let's take a closer look at how a ventilation system can be implemented in an apartment building, but first, you need to contact the professionals of the Veter SPb company to install ventilation systems through the online store: https://veter-spb.com/montazh/montazh-sistem- ventilyacii. Get quality advice on any issues that arise, where they will help you establish high-quality, reliable system ventilation.

In addition to drawings for the placement of air ducts, air distributors, ventilation lines and other elements of the ventilation system, details of ventilation equipment components are developed, energy consumption and overall dimensions are calculated. The ventilation device in a panel house, as well as in a brick house, must be thoughtful and effective, because in addition to ensuring air exchange, it is also important to preserve heat in the home during the winter. In addition, properly equipped ventilation can prevent the spread of fire in the event of an emergency; this is facilitated by the use of fire-resistant materials during installation and the installation of automatic safety valves.

Features of choosing a ventilation system

The choice of ventilation system is made for a specific building, taking into account the number of storeys, category of the building, estimated level of transport noise, and degree of air pollution. Organization of air movement through ventilation ducts, carried out in a natural way(due to temperature and wind pressure differences) is recommended for premises located inside blocks, with a transport noise level not exceeding 50 dBA. Systems with forced exhaust or supply are installed to provide comfortable conditions in buildings where the level of transport noise at the facades exceeds 50 dBA.

Scheme of ventilation ducts in a multi-storey building using a common main shaft, into which air flows from satellite accelerating ducts

Types of ventilation systems used in residential apartments

• ventilation, carried out by the natural removal of air using the draft arising in the ventilation ducts due to the temperature difference and the influx of external air through the vents and windows;
• a combined system with forced removal and natural air supply or, conversely, with mechanical injection of supply air and natural removal;
• completely mechanical both removal of exhaust and injection of fresh air.

Air supply and exhaust in various ventilation systems

The flow of fresh air into the room varies depending on the ventilation system used. If there is no heating of the supply air, it must be supplied to the upper zone to ensure the best mixing with the heated air of the room. In systems where the supply air is heated by heating devices, air from outside is supplied above or behind the devices to ensure its heating. In systems with decentralized flow, where the air is heated using built-in heaters in the supply units, the air is supplied in the upper or lower zone of the room. Air is supplied to living spaces (children's room, office, bedroom and living room).
Exhaust air, regardless of the type of ventilation system, must be removed from the upper zone of kitchens, bathrooms and other auxiliary rooms. Ventilation grates should be located at a height of 2 m (or higher) from the floor level.

Scheme of ventilation ducts with air removal through separate ventilation ducts

Details about ventilation schemes in an apartment building

The ventilation scheme in an apartment building must be carried out with mandatory zoning for cleanliness; the flow of polluted air from auxiliary premises to residential premises must be excluded.
It is advisable to combine the exhaust ventilation shafts of individual rooms into blocks. Air exchange systems with a natural impulse for air inflow and outlet are best done separately (excluding vertical or horizontal collection channels). Ventilation in a multi-storey building can be arranged by connecting the ventilation ducts of different floors to a common (collective) duct.

System diagram natural ventilation with air removal through satellite channels connected to the main channel through one floor

The connection of satellite channels to the prefabricated shaft must be made through one or more floors. The exhaust ducts of the two upper floors should not be connected to the collection duct; a separate outlet is more appropriate.

Depending on the air exchange organization scheme, a distinction is made between ventilation with mixing and ventilation with air displacement. Air exchange with mixing is typical for rooms with airtight vapor barrier, concrete and brick buildings with airtight walls. Both supply and exhaust ventilation carried out using small ventilation windows, door cracks and window openings are also taken into account.

Due to the high local speed of air flows, fresh and polluted air are effectively mixed and removed. In this way, it is impossible to remove all harmful impurities, because there are always zones in the room with almost zero air movement speed. Only proper organization ventilation system can achieve the desired effect.

Wiring diagram of ventilation ducts with connection to the prefabricated ventilation duct through two floors

Most often in Russia, the supply and exhaust ventilation system was previously used. It is carried out due to natural draft arising from the difference in temperature between the internal and external air. The popularity of installing a system in which the source of supply air is the cracks in window frames and open windows are explained by the low cost of the device and simplicity. In addition, natural inflow ventilation required virtually no additional maintenance.

Today, due to tightness modern windows, natural ventilation in an apartment building is ineffective. Only a few of us in the cold season will want to lose precious heat to ensure the necessary air flow. However, even depressurization of the apartment (by opening the window) only brings additional discomfort from increased noise levels (from the street), loss of heat, but still does not provide the necessary air flow for effective ventilation. Humidity increases imperceptibly; in the warm, humid microclimate of an apartment with stale air, excellent conditions are created for the growth of fungi and mold, which is unpleasant and harmful to health.

By installing an adjustable system with natural inflow through supply valves, it is possible not only to ensure the required level of air exchange, but also to reduce the noise penetrating into the apartment. By installing a mechanical exhaust (as well as a mechanical supply and exhaust) ventilation system, it is possible to achieve normalization of the air-thermal conditions of apartments, which will make it possible to significantly reduce the cost of heat generation. By air recovery (recovery of heat from exhaust air), it is possible to maintain an optimal microclimate with low energy consumption.

State of the issue

The use in the mass construction of residential buildings of translucent structures with high tightness of window shutters (in frames made of PVC, laminated wood, aluminum, etc., with two or three sealing contours, sealing of double-glazed windows) has led to the emergence of a number of problems associated with deterioration of indoor air quality, an increase in its relative humidity, the formation of mold on individual structures, damage to the finishing of premises, etc., which has been repeatedly written about on the pages of various specialized publications.

It should be noted that these problems are not unique to our country. There was even a special term that characterizes the state of the parameters of the internal environment of such buildings - “sick building syndrome.” But if in most European countries, increasing the tightness of window units and, accordingly, reducing the air exchange of rooms was considered, first of all, from the standpoint of energy saving (reducing energy costs for heating the supply air) and various types of valves and supply and exhaust systems were provided as compensating measures for the flow of air mechanical ventilation, then in our country the transition to the use of sealed translucent structures took place (and is taking place) with a slightly different motivation (comfortable, beautiful, “no noise”, etc.) and practically without any consideration of the relationship with the microclimate of the premises and work ventilation systems. And often without a basic understanding of this relationship.

In recent years, another problem has been added to the above problems - disruption of the operation of natural ventilation systems, manifested in a change in the direction of air movement in exhaust ventilation ducts (the so-called overturning of the ducts) with the entry of cold outside air into heated rooms. Consequences: a decrease in the temperature of the channel walls, the formation of condensation, frost, ice, up to the defrosting of cold water supply pipelines. Which causes quite natural complaints against builders from consumers.

It should be noted that other malfunctions of the ventilation systems are also possible, in particular, the flow of air through exhaust ducts between individual apartments, the flow of air from a warm attic into apartments on the upper floors, overturning of exhaust shafts and, accordingly, a decrease in air temperature in a warm attic, etc. However, this article discusses precisely the cases of overturning natural ventilation systems with vertical ducts (without a warm attic) - with external cold air entering apartments through one of the exhaust ducts.

Physics of processes

The reasons and conditions for the overturning of individual ducts can be considered using the example of an apartment on the top floor of a multi-storey residential building with independent ventilation ducts located in the bathroom and kitchen.

Under the influence of thermal pressure differences, exhaust ducts remove air from the apartment, creating a certain vacuum, as a result of which air must flow into the living quarters through leaks in the enclosing structures or open vents. Fresh air. And if the sashes of the window units are open in at least one of the rooms, then air flow is ensured and the exhaust ducts work for exhaust - as envisaged by the project. But if the sashes of the window blocks are closed, they themselves window units made with good seal porches, then the air flow into the apartment sharply decreases, the air flow through the exhaust ducts decreases accordingly, and the system as a whole enters an unstable equilibrium mode: there is a pressure difference, the ducts are filled with warm air, but there is practically no air movement through the ducts - due to insufficient inflow. The system "stops".

And in this situation, a small pressure difference caused by gusts of wind, opening the front door, temperature differences in individual rooms or different elevations of the ventilation shaft heads is sufficient for one of the channels to “overturn.” In this case, the “overturned” channel is filled with cold air, its walls are cooled, and an additional pressure drop appears due to the difference in the densities of warm and cold air in various channels one apartment, and the system moves to a new one steady state with the entry of outside air into the apartment through the exhaust duct.

It should be noted that attempts to start overturned channels by heating them gas burners, connecting fans, increasing the height of the heads, as a rule, do not have an effect, since the causes of overturning are not eliminated.

If the ducts are located in different parts of the apartment (for example, the bathroom is in the bedroom area, and the kitchen is adjacent to the hallway), then cold air moves along the corridor from one of the ducts to the others. As a rule, one duct in an apartment “overturns”, while other exhaust ducts begin to work harder for exhaust.

When you open the sash of a window unit (any one - in the kitchen or in the common room), the apartment’s ventilation system goes into design mode - with air removed through all exhaust ducts. But when the sash is closed, everything returns to its previous state.

Aerodynamic calculations of ventilation using a special computer program show that when the characteristics of modern windows are included in the calculation, disruption of the ventilation system occurs at almost any outside air temperature. At the same time, when the characteristics of “old” window blocks (without sealing the window shutters) are included in the calculation, the exhaust ducts work for exhaust even when the windows are closed.

In multi-storey buildings with vertical collection channels and satellite channels, the pressure distribution along the height is more complex nature. Characteristics influence entrance doors, staircase, the dimensions of the prefabricated channel and satellite channels, not to mention the wind or open sashes of window units on individual floors. However, in general, the described relationship remains valid for multi-story buildings. In practice, there have been cases of the collection channel overturning completely along the entire riser - from the top floor to the basement of a ten-story residential building.

What to do?

Traditional questions that arise in such situations are “who is to blame” and “what to do”?

As a rule, claims for “improper” operation of ventilation systems are presented to builders: “...deviations from the project”, “...quality of work”, etc. But, despite the fact that in some cases certain implementation costs design solutions take place on construction site, the main reasons lie deeper and are caused, first of all, by omissions or errors made at the project development stage - when choosing the basic design of the ventilation system, carrying out aerodynamic calculations and justifying the design parameters of the system. Although it should be noted that it is difficult to fully call these omissions errors, since until recently there were no regulatory and methodological documents prescribing the procedures for such calculations in relation to natural ventilation systems, taking into account the characteristics of modern enclosing structures.

In this regard, we can quote an excerpt from SNiP 01/31/2003“Residential multi-apartment buildings” “...In residential premises and kitchens, air flow is ensured through adjustable window sashes, transoms, vents, valves or other devices, including autonomous wall air valves with adjustable opening...”. That is, formally SNiP 01/31/2003 allows ventilation through periodically opening vents or sashes of window blocks, which is what designers refer to in critical situations.

But the same SNiP also stipulates the requirements for air exchange of premises - in non-working mode, the air exchange rate must be no less than n = 0.2 for living rooms and no less n = 0.5 for kitchens and bathrooms. That is, even if there are no people in the apartment, the ventilation system must provide a certain air exchange. For example, in a typical three-room apartment– not less than 40 m3/h. How to ensure this air exchange is the task of designers. When the sashes are closed, window blocks made of PVC profiles or laminated wood do not provide even 20% of the required air flow.

The question “what to do” can be divided into several specific sub-questions:

• what to do when designing natural ventilation systems in order to eliminate such results at the project development stage (it should be noted that this is the most complex issue, requiring separate consideration);
• what to do during construction (how to protect yourself if a building with a similar ventilation system is already under construction);
• what to do if the building is built and the described phenomena manifest themselves in full already at the operation stage.

At first glance, the obvious and simple answer to all these questions is to ensure an organized air flow by installing supply valves. Since they have learned how to make window units so airtight, it is necessary to make additional, adjustable “window windows” along with them – “autonomous valves” for organized air flow, and, accordingly, depressurize the apartments. It should be noted that at present, supply valves of this kind are quite widely represented on the domestic market, some experience in their operation has been accumulated, and there is already plenty to choose from.

However, just installing supply valves does not guarantee stable operation of the natural ventilation system. Inlet valves are a necessary but not sufficient condition.

The reasons are as follows:

• firstly, when operating a building, no one can guarantee that in individual apartments (and perhaps in all apartments, for example, at the stage of completion of construction or initial stage operation of the house) the valves can be closed; and, accordingly, the ventilation system may again be in an unstable state; secondly, the difference in aerodynamic resistance supply valves (even when fully open) and exhaust ducts.

As an example in table. 2 shows the resistance characteristics of some supply valves, window units and exhaust ventilation ducts. The differences in resistance characteristics are several orders of magnitude.

In other words, in a modern apartment equipped with supply valves, for example window valves or wall valves, the main pressure losses (resistance to air movement) occur not in the exhaust ducts, as is assumed in traditional calculations, but in the inflow (supply valves and windows). And, accordingly, for successful work ventilation systems require careful coordination of exhaust ducts, both with supply ducts ventilation devices, and among themselves. Under the word "linkage" in in this case this implies the selection of characteristics of supply valves (number, resistance to air passage, flow rate) and characteristics of exhaust ducts (number, dimensions, height of heads, etc.); if necessary, increase the channel resistance by installing louvered grilles, exhaust valves or throttling liners.

This task is especially relevant for apartments on the upper floors of multi-story buildings, which, as a rule, have their own exhaust ducts (with very little resistance), as well as in cases where the heads of the ventilation shafts are at different elevations and the operation of the ventilation systems is also influenced by the difference in available pressures in exhaust ducts of different heights.

Thus, to ensure stable operation of natural ventilation systems in residential multi-apartment buildings and prevent exhaust ducts from tipping over, it seems necessary:

1. Mandatory use of air supply devices that provide a controlled flow of fresh air into living rooms.

2. At the design stage of ventilation systems - careful coordination of exhaust ducts with supply ventilation devices and with each other. If it is not possible to provide the required cross-section of exhaust ducts (for example, in large-panel buildings with factory-made ventilation units), it is necessary to provide for the installation of throttling liners with calibrated holes, indicate their number, installation location, diameter of the holes with a layout by floor (as was done during the design heating systems with throttling washers on risers).

Ideally, residential building designs should include the installation of special exhaust valves on ventilation ducts to ensure automatic regulation air flow depending on the operating mode of the apartment, including the functions of the check valve. The resistance of the exhaust valves should change taking into account the operating mode of the supply devices or the degree of opening of the window sashes. The principal characteristics of such devices are shown in Fig. 4.

3. When putting a residential building into operation - commissioning adjustment of exhaust ducts and air supply devices. The performance assessment of ventilation systems should be carried out both with open and closed sashes of window units. In accordance with the requirements of SNiP 31-01-2003, the ventilation system must ensure continuous air exchange even with the windows closed.

If appropriate solutions were not provided for at the construction stage and air overturning in the ducts was detected already during the operation of the building, the following sequence of actions can be recommended:

• to bring the system into design mode, cover (or completely close) the exhaust ducts operating for exhaust; at first glance, this advice may seem strange, since in order to reduce the influx of cold air, it seems that it is necessary to block the channels that work for the influx (which is what residents try to do in such situations); however, only by blocking the exhaust channels can one “force” the overturned channels to start working in the design mode; to speed up this process, you can slightly open one of the window sashes;
• install (mount) in each living room, with the exception of the kitchen and bathrooms, window or wall valves with adjustable air flow;
• further - install throttling liners with holes with a diameter of 40-50 mm in all channels of the apartment, thus increasing the resistance of the exhaust channels; Any type can be used as throttling inserts sheet material- expanded polystyrene, plasterboard, polyurethane, which can be easily inserted into exhaust ducts;
• after the system reaches design mode, you can replace the throttling liners in the ventilation ducts with louvered grilles with an adjustable cross-section; select the opening mode for the dampers of the supply valves and louvered grilles that ensure the required air exchange in the apartment.

The difficulty of implementing the above recommendations is partly due to the fact that in ventilation systems with vertical prefabricated ducts, the above measures must be carried out in almost all apartments located along the same riser (at least in no less than 60% of apartments). Otherwise, it is possible that air will flow through the collection channel into apartments on other floors.

In emergency situations, for example, when the operation of ventilation systems is disrupted during a period of sudden cold snap, a simpler solution is possible - by reducing the cross-section of the channels ("squeezing" all channels) at the mouth of the exhaust ventilation shafts - from the roof side. However, this solution significantly reduces the air exchange of all apartments and can only be considered as a short-term measure aimed at preventing damage.

It should be noted that the above problems are typical, first of all, for ventilation systems with vertical ducts opening directly into the atmosphere - without a warm attic. Ventilation systems with a warm attic are more resistant to tipping - due to the presence of a common chamber - attic space, equalizing pressure between individual channels of apartments. However, even in these ventilation systems it is necessary to take into account the above recommendations.

The composition of the air and the health of the residents there will depend on how ventilation is installed in multi-storey buildings.

Many people want to make their stay more comfortable and cozy. But the opposite happens. Without thinking about the consequences or out of ignorance, they disrupt air exchange, which leads to negative consequences. The purpose of this article is to explain how the ventilation system functions in an apartment building, what factors disrupt its operation and what problems this leads to.

Selection criteria, types and elements of ventilation in an apartment building

The presence of certain elements will directly depend only on the type of system. But, regardless of the chosen option, it will contain the following mandatory components:

• air channels;
• ventilation shaft;

Regardless of the type, it will definitely be a supply and exhaust system. Accordingly, it is necessary to ensure not only the exhaust, but also the arrival in the same volume.

Depending on the type of impulse to initiate cravings, such systems are usually divided into:

• natural - traction appears due to the difference in temperature and pressure indoors and outdoors;
• combined - exhaust or injection is carried out electromechanically;
• forced - draft and injection occurs with the help of special fans and other devices.

If natural ventilation of residential buildings is used in a multi-storey building, the presence of a ventilation shaft is mandatory.

Diagram of a typical communal ventilation shaft

The requirements for its arrangement are simple and the same for all buildings:

• tightness;
• throughput corresponds to the designed volume;
• compliance with sanitary and hygienic standards;
• fire safety.

Also, depending on the air exchange pattern, the system can be mixing or displacement. The first method is typical for impenetrable walls with a vapor barrier. The influx comes through ventilation holes and various cracks. Due to the relatively high initial speed, fresh street air mixes with polluted air. If the flow is not organized correctly, it will be difficult to extract air contaminated with impurities in this way.

To select the type of ventilation, it is necessary to take into account all factors, such as:

• number of floors;
• location relative to other structures;
• level of external noise;
• environmental pollution.

For houses with intra-block location and noise levels up to 51 dBA, it is recommended to install natural ventilation. If the building is located in a particularly polluted place, or the noise level is more than 51 dBA, it is necessary to use an air supply system and it is advisable to carry out filtration.

Arrangement of ventilation elements in a high-rise building

The location of air intake from the street is installed in certain places, depending on how the ventilation in the apartment building is arranged. If heating of the drawn air is not provided in the system under consideration, it must be brought as close as possible to the ceiling of the room. This will ensure that it is completely mixed with the warmer air in the room.

So that the penetrating air is heated under the influence heating devices installed in the apartment, input is carried out near these devices.

When heating occurs directly in the blowers, the supply is equipped at the bottom of the room.

Regardless of the type of system, inflow occurs only in living rooms, and exhaust in the kitchen and bathroom. The hole for the hood is installed at a height of at least 2 meters from the floor. The ventilation scheme in a multi-storey building assumes that there is no movement of air from sanitary and additional premises to living rooms.

Ventilation ducts of different rooms with natural exhaust It is recommended to provide separate air pollutants, excluding single-level assemblies. If such a possibility is not available in an apartment building, it is necessary to provide for the supply of separate pipes into one vertical shaft.

They join such a shaft mainly once every two floors. Ventilation on top floor is output separately; it is not recommended to connect it to the shaft.

Features of arrangement and functioning in panel houses

If we talk about this common type of house, then the air exchange there is arranged according to a natural principle. The system is designed in exactly the same way in old brick houses, as well as in low-budget new buildings. Street air is sucked in through cracks and leaks in old frames or through special holes provided in modern plastic ones.

The drainage in them occurs due to the presence of a constant draft present inside the ventilation shaft-channel, which rises above the ridge of the roof or goes into the attic. Street air, entering living spaces through windows, thanks to the draft in the duct, tends to the exhaust vent in the bathroom or the hood in the kitchen. It turns out that the air, passing through all the rooms of the apartment, gradually displaces the polluted air into the street.

The order of operation of ventilation using the example of a typical project

The most common panel project is a nine-story building. The principle of operation of the hood is the same. Air from the street, through windows and cracks, enters the apartment. The exhaust occurs through satellite ventilation ducts in the kitchen or bathroom. One, or less often several, channels from the hood are connected to the main pipe. These channels are connected to the main shaft through two floors. These shafts are quite bulky and take up a lot of space. A large-panel house will most likely be equipped with such a system.

Such a scheme for a house of 9 floors assumes the presence of a warm attic. The outlet from the 8th and 9th floors goes directly into the atmosphere, bypassing the common channel. The scheme for a 9-storey building was designed based on the complete absence of wind and an outside air temperature of +5.

Despite the fact that natural ventilation in such houses is not very effective, it requires almost no maintenance, and blockages rarely occur. There have been cases where the ventilation ducts became clogged building materials during the construction of the house. Such a surprise subsequently affected the quality of the hood. Most often, cleaning the mine is required once every 5-6 years.

During repairs, many people block the air flow in some place. They unknowingly think that this will not affect the hood, but the process of air renewal in the apartment becomes difficult or stops completely.

The most common actions leading to interference and disruption of natural ventilation:

• installation of sealed plastic windows;
• interior doors with seal;
• installation of various fans in the hood.

In order not to disrupt the operation of the natural ventilation draft, it is forbidden to obstruct the inflow and outflow of air. For plastic windows, it is necessary to install inlet openings or arrange an external inlet separately. Doors between rooms are equipped with bars at the bottom. The cross-section of the exhaust duct should not be blocked by fans.

Possible options for arranging ventilation in high-rise buildings

Modern ventilation in a panel house is equipped with single exhaust pipes. From the sanitary facilities, each floor has its own pipe going to the roof. In this option, there is no possibility of penetration of foreign odors and the entire system functions evenly and reliably.

Another good option is when all vertical channels flow into a common horizontal collection manifold, which is located in the attic. The air from it exits to the street through one common pipe.

The most unstable method is when a small satellite channel from each apartment enters a common ventilation shaft. This ventilation scheme in a panel house is significantly cheaper to install and increases living space, but constantly brings a lot of problems to residents. The most common one is the flow of various odors from one apartment to another.

The best ventilation option is electromechanical forced air supply and exhaust systems. They are used in modern new buildings, except low-budget ones. The supply installation of such a system is located in basement or on the side of the main building. It supplies filtered and heated or cooled air to all rooms and spaces. On the roof, in turn, there is an electric exhaust fan with exactly the same design power as the supply fan. It is designed to remove contaminated mixtures from apartments through hoods.

This is one of the primitive schemes of the device. A more complex one, which can be equipped in a modern high-rise building, is equipped using new energy-saving technologies. For example, recuperators are devices that allow you to take heat or cold from the exhaust air and give it to the supply air.

The consequence of installing modern sealed windows and doors is the unsatisfactory performance of ventilation elements and its non-compliance with SNiP recommendations. Few people are ready to keep the windows slightly open at any time of the year to bring in the required amount of air, even in cold weather. In the absence of efficient operation of the hood, the humidity indicator increases and air saturation increases carbon dioxide, and with oxygen it decreases. In such a room microclimate, when air humidity is higher than normal, mold and various fungi multiply well. This is very harmful to the human body and is not aesthetically pleasing.

The way out of the situation is quite simple. You need to get one. It will eliminate the problems of air renewal, and the use of a recovery system allows you to maintain a comfortable microclimate and fresh air during minimum costs energy.