Living quarters only extract air. Natural ventilation of residential buildings

Natural ventilation system in a private house - features and disadvantages

The natural ventilation system in a private house consists of vertical channels that start in a ventilated room and end above the roof ridge.

The movement of air up the channels occurs under the action of forces (traction) caused by the difference in air temperatures at the inlet and outlet of the channel. Warm indoor air is lighter than cold outdoor air.

The draft in the ventilation duct is also affected by the wind, which can either increase or decrease the draft. The traction force also depends on other factors: the height and section of the ventilation duct, the presence of turns and narrowings, the thermal insulation of the duct, etc.

Scheme of ventilation of premises in a multi-storey private house

By building regulations natural ventilation channel should provide normative air exchange at an outside air temperature of +5 about C , excluding wind effects.

In summer, when the air temperature in the street is higher than the specified one, the air exchange deteriorates. Air circulation through the channels of natural ventilation almost completely stops when the outside temperature is above +15 about C.

In winter, the colder it is outside, the stronger the draft and the higher. Heat loss in winter through the natural ventilation system, according to some estimates, can reach 40% of all heat loss at home.

In houses, natural ventilation ducts usually exit from the kitchen, bathrooms, boiler room and dressing rooms. Additional channels are arranged for ventilation of the basement or, for the device.

On the upper floors of a private house it is also often necessary to arrange additional channels of natural ventilation from living rooms to provide the required air exchange.

In attic rooms natural ventilation, as a rule, cannot provide the required air exchange due to a lack of draft in ventilation ducts of low height.

Norms of natural ventilation

Russian building regulations SP 55.13330.2011 "Single-apartment residential houses", paragraph 8.4. require:

The minimum performance of the ventilation system at home in maintenance mode should be determined from the calculation at least one exchange of air volume per hour in premises with permanent residence of people.

From the kitchen in maintenance mode, at least 60 m 3 of air per hour should be removed, from the bath, lavatory - 25 m 3 of air per hour.

The air exchange rate in other rooms, as well as in all ventilated rooms in non-working mode, should be at least 0.2 room volume per hour.

A room with a permanent stay of people is a room in which the stay of people is provided for at least 2 hours continuously or 6 hours in total during the day.

For comparison, I will give the requirements for ventilation performance in apartment building, least:

The amount of air exchange specified in the standards must be provided for the design conditions: outdoor air temperature +5 about C, and the temperature of the indoor air of the room during the cold season, (for residential premises +22 about C) .

The intake of outside air into the premises should be provided through special supply devices in the outer walls or windows.

For apartments and premises, where at an outdoor temperature of +5 °C removal of the rated air flow is not ensured, mechanical exhaust ventilation should be provided.

Mechanical ventilation with partial use of natural ventilation systems for the supply or removal of air (mixed ventilation) should also be provided during periods of the year when microclimate parameters and air quality cannot be provided by natural ventilation.

For example, when the outside temperature is above +5 o C, the performance of natural ventilation ducts is reduced. In this case, it is allowed to increase air exchange in rooms with windows by opening windows, vents and transoms. In rooms without windows, mechanical forced exhaust ventilation should be provided.

The natural ventilation system in a private house works as follows

In old houses, apartments, fresh air from the street penetrates into living rooms through leaks in wooden windows, then through the overflow holes in the doors(usually a gap between the edge of the door and the floor) reaches the kitchen and bathrooms and exits into the natural ventilation channel.

The main purpose of such ventilation is the removal of gas combustion products, moisture and odors from the kitchen and bathrooms. Living rooms in such a system are not sufficiently ventilated. In the rooms for ventilation it is necessary to open the windows.

In the case of using modern hermetic window structures in the house, for the inflow of fresh air, it is necessary to install special supply valves in the outer walls of the rooms or in the windows.

Often, supply valves are not made even in new houses. For air supply having to keep the window sashes open all the time, at best, by installing “micro-ventilation” fittings on the windows for this. (First we choose and pay money for airtight windows with several levels of seals to protect against cold, noise and dust, and then we keep them constantly ajar!? :-?)

It is also common to see airtight doors installed in the premises of a house, without a gap near the floor or other opening for air to pass through. Installation of hermetic doors overlaps natural circulation air between rooms.

Many are not even aware of the need provide a constant supply of fresh air to the rooms and air circulation between the rooms. By setting plastic windows and hermetic doors, and live in stuffiness, with condensation and mold. And in the air of the premises, an increased concentration of deadly gases - and insidious.

Disadvantages of natural ventilation

All these open vents, ajar sashes, cracks in windows, openings-valves in the outer walls and windows cause drafts, serve as a source of street dust, allergenic plant pollen, insects and street noise.

The main disadvantage of natural ventilation in our homes is the lack of control and regulation of the amount of air supplied to and removed from the premises.

As a result, often stuffy in the house high humidity air, condensation on the windows and in other places, fungus and mold appear. Usually, this indicates that ventilation does not cope with its task - to remove pollution, pollution and excess moisture released into the air. The amount of air leaving through the ventilation is clearly not enough.

In other houses in winter, it is more often the other way around, the air is very dry with relative humidity less than 30% (comfortable humidity 40-60%). This indicates that too much air is escaping through the ventilation. The frosty dry air entering the house does not have time to be saturated with moisture and immediately goes into the ventilation duct. And heat goes with the air. We get indoor microclimate discomfort and heat loss.

V summer time draft in the natural ventilation channel decreases, up to the complete cessation of air movement in the channel. In this case, the rooms are ventilated by opening the windows. Other rooms without windows, for example, a bathroom, a toilet, a dressing room, cannot be ventilated in this way. Such rooms that are left without ventilation in summer, humid air easily and quickly accumulates and then appears, smell, fungus and mold.

How to improve natural ventilation

The work of natural ventilation can be made more economical, if an automatic valve controlled by a humidity sensor is installed at the inlet to the ventilation duct. The degree of opening of the valve will depend on the humidity of the air in the room - the higher the humidity, the more the valve is open.

Installed in the rooms supply valves controlled by an outdoor temperature sensor. As the temperature decreases, the density of the air increases and the valve must be closed to prevent excess cold air from entering the room.

Automation of the valves will reduce heat loss with the air leaving through the ventilation by 20-30%, and the total heat loss of the house by 7-10%.

It should be understood that such local automation of the operation of each individual valve will not be able to fully eliminate the shortcomings of the natural ventilation system in the house. Installing automatic valves will only slightly improve ventilation, especially in winter.

It is possible, at a minimum, to install adjustable grilles and valves on the supply and exhaust ducts, and adjust them manually at least twice a year. On the winter period cover, and with the onset of heat, the exhaust grilles and supply valves open completely.

Building regulations allow the air exchange rate in the non-working mode of the premises to be reduced to 0.2 room volume per hour, i.e. five times. There will always be rarely used rooms in the house. Especially on the upper floors of the house. In winter, be sure to close ventilation valves in rarely used rooms.

ventilator in outer wall provides forced air flow into the room. Fan power only 3 -7 Tue.

The ventilator has the following advantages over a supply valve:

The volume of air coming from the street is limited only by the fan power.
They create excessive pressure in the room, due to which, in houses and apartments with a poorly functioning exhaust ventilation channel, air exchange increases, and polluted air from neighboring rooms and the basement is excluded.
Reduce the dependence of natural ventilation on climatic factors.
Achievable deep air purification from dust, allergens and odors as a result of the use of more efficient filters with high aerodynamic resistance.
Provide the best.

Ventilators equipped with an electronic climate control system, air heating, special filters are often called breathers.

Inexpensive electronic devices are commercially available for home use that measure air humidity. Hang this device on the wall and adjust throughput ventilation channels, focusing on the readings of the device. Maintain optimal humidity in residential areas of 40-60%.

Check for the presence and size of vents to move air between rooms in the house. The area of the overflow opening for air outlet from the living room must be at least 200 cm 2. Usually leave a gap between the edge of the door and the floor in a room with a height of 2-3 cm.

Overflow opening for air inlet to the kitchen, bathroom or to another room equipped with a ventilation exhaust duct, should be at least 800 cm 2. Here it is better to install a ventilation grill at the bottom of the door or inner wall premises.

When moving from a room to a room with a ventilation duct, the air must pass through no more than two overflow openings (two doors).

Ventilation ducts that pass through an unheated room (attic) must be insulated. The rapid cooling of the air in the duct reduces the draft and leads to condensation from the exhaust air. The route of the natural ventilation channel should not have horizontal sections, which also reduce draft.

Fan in natural ventilation duct

To improve the operation of natural ventilation, kitchen hoods are installed, as well as electric fans at the inlet of ventilation ducts. Such fans are suitable only for short-term and intensive ventilation of premises during periods of significant release of moisture and pollution. The fans are very noisy, their performance, and hence the power consumption, exceeds the values \u200b\u200bnecessary for constant ventilation.

It should be noted that installing a fan in an existing natural ventilation duct reduces the clearance of the duct. The autorotation of the blades (rotation under the pressure of the incoming air of the blades of a non-working fan) further increases the aerodynamic resistance of the channel. As a result, setting fan significantly reduces the force of natural draft in the channel.

A similar situation is when the kitchen hood above the stove is connected to the only natural ventilation channel in the kitchen.

Filters, valves and a fan in the kitchen hood practically block the natural draft in the ventilation duct. A kitchen with the hood turned off remains without ventilation, which worsens the air exchange throughout the house.

To remedy the situation, in the air duct between the natural ventilation channel and the kitchen hood it is recommended to place a tee with a check valve on the side outlet. When the hood is not working check valve opens, allowing free passage of air from the kitchen to the ventilation duct.

When turning on the cooker hood a large amount of warm air is thrown out into the street for the sole purpose of removing odors and other contaminants that form over the stove.

To eliminate heat loss, it is recommended to install an umbrella over the stove, equipped with a fan, filters and odor absorbers for deep air purification. After filtering, the air purified from odors and pollution is sent back to the room. Such an umbrella is often called a filter hood with recirculation. It should be borne in mind that the savings from lower heating costs are somewhat leveled due to the need to periodically replace the filters in the hood.

Available for sale fans controlled by a humidity sensor. The fan turns on when a certain threshold of humidity in the room is reached and turns off when it decreases. All the above features of the operation of fans in the natural ventilation system are also preserved when working with a humidity sensor.

In any case, the operation of the fan only leads to an increase in draft in the ventilation duct and a decrease in humidity in the room. But he is not able to limit natural draft, preventing excessive dryness of the air and heat loss in winter.

In addition, in the natural ventilation system, several elements located in different parts of the house work in concert - supply valves, exhaust ducts, overflow grilles between rooms.

Turning on a fan in one of the channels often leads to a disruption in the operation of other elements of the system. For example, air inlets in a home often fail to let through the sudden increase in air required to run a fan. As a result, when the hood in the kitchen is turned on, the draft in the exhaust duct in the bathroom overturns - air from the street begins to enter the house through the exhaust duct in the bathroom.

Natural ventilation in a private house is a system:

simple and cheap to install;
does not have any mechanisms requiring an electric drive;
reliable, does not break;
very cheap to operate - the costs are associated only with the need to perform periodic inspections and cleaning of ventilation ducts;
does not make noise;
the efficiency of its work is highly dependent on atmospheric conditions - most of the time the ventilation does not work in the optimal mode;
It has limited opportunity adjusting its performance, only in the direction of reducing air exchange;
in winter, the operation of the natural ventilation system leads to significant heat losses;
in summer, the ventilation system does not work, ventilation of the premises is possible only through open windows, vents;
there is no possibility of preparing the air supplied to the room - filtering, heating or cooling, changing humidity;
does not provide the necessary comfort (air exchange) - which causes stuffiness, dampness (fungi, mold) and drafts, and also serves as a source of street dust (plant pollen) and insects, reduces the sound insulation of rooms.

Ventilation of the upper floors of a multi-storey private house

In a multi-storey building, as in a large ventilation duct, there is a natural draft, under the influence of which air from the first floor rushes up the clearance of the stairs to the upper floors.

If no measures are taken, then on the upper floors of the house we will always have stuffiness and high humidity, and in the house there will be a temperature difference between floors.

There are two options for natural ventilation of the upper floors of the house.

Read:

Ventilation in a wooden house

Interestingly, traditional for Russia houses with walls made of logs or timber do not have special devices for ventilation. Ventilation of the premises in such houses occurs due to walls (“breathing walls”), ceilings and windows, as well as as a result of air moving through the chimney when the stove is fired.

In the constructions of a modern wooden house, more and more often they use various ways sealing - machine profiling of the mating surfaces of logs and beams, sealants for interventional seams, vapor-tight and wind-proof films in ceilings, sealed windows. The walls of the house are sheathed and insulated, treated with various poisonous compounds.

In the rooms of the house, as a rule, there are no stoves.

The ventilation system in such modern wooden houses is simply necessary.

Ventilation of wardrobes and pantries

In the dressing room, pantry must be made ventilation. Without ventilation, the rooms will smell, humidity will increase, and even condensation, fungus and mold may appear on the walls.

The scheme of natural ventilation of these rooms should exclude the flow of air from the dressing room or pantry into the living rooms.

If the doors of these rooms open onto a corridor, a hall or a kitchen, then the rooms are ventilated in the same way as the living rooms in the house are ventilated. For the influx of fresh air from the street, a supply valve is placed in the window (if any) or in the wall. In the dressing room door, closets leave a gap below, between the door and the floor, or make another hole for air to pass through, for example, a ventilation grill is inserted into the bottom of the door.

Fresh air enters the dressing room or pantry through the supply valve, then leaves through the hole in the door to the corridor, and then goes to the kitchen, to the exhaust duct of the natural ventilation of the house.

Between the dressing room or storage room and the room where there is a natural ventilation channel there should be more than two doors.

If the doors of the dressing room open into the living room, then the movement of air for ventilation of the dressing room should be organized in the opposite direction - from the living room, through the hole in the door, into the ventilation duct of the dressing room. In this variant the dressing room is equipped with a natural ventilation channel.

Ventilation in your city

Ventilation

Ventilation of a private house. Air flow in the house - video:

The purpose of ventilation is to improve the air quality in the home. There is a conflict between the need to improve air quality and minimize device costs modern ventilation and reduce its energy consumption.

Meanwhile, ventilation is not the only way to improve indoor air quality. The most important is the control of sources of air pollution. We are talking about everyday habits, such as no smoking in the room, taking care that bacteria and fungi do not multiply in the apartment.

The quality of the air in the house clearly depends on whether materials with low level harmful secretions. natural materials, such as wood, stone or glass, are considered primarily as such.

With a reasonable choice of materials at the construction stage, good quality home air can be maintained even if a less expensive and energy intensive ventilation system is installed.

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 an 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 units 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"

Natural type of ventilation can be found in brick house old housing stock, where air enters through the gaps of the porches wooden windows, doors, and the hood is carried out by a draft inside a vertical channel, with an exit 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 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 used today 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.

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

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

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

Air exchange rates in residential buildings

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

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

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

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

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

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

For example:

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

Air exchange rates for office buildings

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

The main requirements for such ventilation include:

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

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

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

Organization of air exchange in a private house

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

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

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

The incoming air in the dwelling must first pass through the window or open window sashes, the supply valve is located with outer side walls of the dwelling, then, passing through the room, penetrates under door leaf or through special ventilation holes and gets into the bathrooms and kitchen. It takes longer to go out through the exhaust system.

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

Why is air exchange necessary?

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

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

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

How to check if ventilation is working?

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

Description:

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

Natural ventilation of residential buildings

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

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

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 toilets, bathrooms and kitchens, which, depending on the type cooker is 110 - 140 m 3 / h, or an 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 principal solution for natural exhaust ventilation systems in multi-storey buildings is a scheme that includes a vertical collection channel - "trunk" - with side branches - "satellites". Air enters the side branch through an exhaust opening located in the kitchen, bathroom or toilet and, as a rule, in the interfloor ceiling above the next floor, is bypassed into the main collection channel. Such a scheme is much more compact than a system with individual channels, can be aerodynamically stable and meets the requirements of fire safety.

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

In typical buildings, the main element of the natural ventilation system is a floor ventilation unit. In buildings 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. For its sealing is still sometimes used cement mortar, 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.

Besides constructive solutions 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.

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.

Aeromat accommodation options

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

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

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

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

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

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

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

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

Figure 4a shows that with normative windows and doors and closed vents, the flow rates of air removed through the exhaust ventilation are almost equal to the flow rates of infiltration air during the entire heating season in windy and calm conditions. There is practically no air movement through the apartment doors (all doors work for inflow with a flow rate of 0.5 - 3 m 3 / h m 2). Infiltration is observed through the windows of the windward and leeward facades. The costs on the top floor refer to the duplex apartment, which explains the increased costs. It can be seen that the ventilation works 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.

Organized natural ventilation in a residential building is an air exchange that occurs due to the difference in air density inside the building and outside, through specially arranged exhaust and supply openings.

For ventilation of premises in a residential building, a natural ventilation system is provided. Let's see how it works and how it works.

Natural ventilation device

Each entrance from the first floor to the last has a common ventilation duct that runs vertically from the bottom, up with access either to the attic or directly to the roof (depending on the project). Satellite channels are connected to the main ventilation duct, the beginning of which is located, as a rule, in the bathroom, kitchen and toilet.

Through these satellite channels, the "exhaust" air leaves the apartments, enters the common ventilation shaft, passes through it and is discharged into the atmosphere.

It seems that everything is extremely simple and such a mechanism should work flawlessly. But there are many things that can interfere with the normal operation of ventilation.

The most important thing in the work of natural ventilation is that air must be supplied to the apartment in sufficient quantities. According to projects, according to SNiP, this air should flow through "leaks" window openings, as well as by opening the vents.

Extract from SNiP 2.08.01-89 (minimum air exchange parameters for an apartment).

But we all understand that modern windows in the closed state do not let in any sounds, let alone air. It turns out that you need to keep the windows open all the time, which of course is not possible for a number of reasons.

Causes of disruption of natural ventilation

Re-equipment of ventilation channels

It happens that the ventilation stops working due to active neighbors who could simply break the ventilation duct to expand the living space. In this case, for all residents whose apartments are located below, the ventilation will stop working.

Garbage in ventilation duct

It often happens that something gets into the ventilation shaft and simply does not allow air to move freely. If this happens, then you need to contact the appropriate structure, it is forbidden to climb into the ventilation duct on your own.

Incorrect connection of exhaust hoods

Connectivity is also a common problem. kitchen hoods(exhaust hoods) of high power to a satellite channel that is not intended for this. And when such a hood is turned on, an air lock forms in the common ventilation duct, which disrupts the operation of the entire system.

seasonality

Unfortunately, the operation of the natural ventilation system is also affected temperature regime, in the cold season, it works better, and in summer, when the temperature rises outside, it works weaker. To this, several negative points described above are added, and the operation of the entire system comes to naught.

And of course, there are mistakes during construction made by the contractor for one reason or another ... Only the installation of supply and exhaust ventilation equipment will help here.

Natural ventilation works all year round 24 hours a day. Therefore, a round-the-clock supply of air to the room is necessary. If it is not there, then in winter, when the windows are closed, condensation may occur, an increase in humidity up to the formation of mold, to avoid this, install supply valves, this will improve ventilation in the room and get rid of excess moisture.

For the organization of good air exchange in the apartment all year round. A ventilator will be required. Thanks to this device, you do not have to open windows, and fresh and clean air will always enter the apartment.