Heating and ventilation systems play a major role in creating healthy working conditions. In 1884, the Russian scientist I. Flavitsky created the so-called thermal theory, proving that a person’s well-being depends on the combination of three parameters of the air around him: temperature, humidity and speed of movement. This theory was further developed, and the complex of three parameters began to be called a meteorological factor.

Normalization of the air environment of industrial premises is carried out in the following ways:

Maintaining a standardized value of barometric pressure (vacuum in production premises is not allowed);

natural and mechanical ventilation;

air conditioning;

localization of harmful factors;

heating;

automatic control and alarm;

air deodorization (elimination of unpleasant odors).

The microclimate and air purity at enterprises are regulated in accordance with the requirements of SanPiN 2.2.4.548-96 “ Hygienic requirements to the microclimate of industrial premises" and a number of other GOSTs from the system of occupational safety standards.

Causes and nature of air pollution in enterprises

For the normal functioning of the human body, it is necessary that the air in work areas be close in composition to atmospheric air. However, it is almost impossible to create such air conditions in industrial premises. At service enterprises (sewing, shoe, Catering etc.) various harmful gases, vapors and dust are released. The content of harmful substances in the air of industrial premises should not exceed the maximum permissible concentration (MPC). According to the state standard, the maximum permissible concentrations of harmful substances in the air of a working area are concentrations that, during daily (except weekends) work for 8 hours or for another duration, but not more than 41 hours per week during the entire working period, cannot cause diseases or abnormalities in the state of health, detected by modern research methods in the process of work or in the long term of life of the present or subsequent generations.

The unit of measurement for MPC is mg/m3.

There may be various harmful substances in the air that have a unidirectional effect on humans. For such substances contained in the air in concentrations C 1, C 2,. . . , C n and having, respectively, MPC 1, MPC 2, . . . , MPC n , the following relation must be satisfied

C 1 / MPC 1 + C 2 / MPC 2 + . . . + C n / MPC n< 1.

When several types of harmful substances that do not have a unidirectional effect are simultaneously contained in the air, their maximum permissible concentrations remain the same as with their isolated effects.

Based on the degree of impact on the human body, harmful substances are divided into four hazard classes; 1st – extremely dangerous substances; 2nd – highly hazardous substances; 3rd – moderately hazardous substances; 4th substances are low hazardous. This classification is based on indicators characterizing the maximum permissible concentrations of harmful substances and their average lethal concentration in the air.

MPCs apply to the air in the working area of all workplaces, regardless of their location in production premises and in open areas.

A work area is considered to be a space 2 m high above the level of the floor or platform, in which there are places of permanent or temporary residence of workers. A permanent workplace is considered to be a place where a worker spends more than 50% of his working time or more than 2 hours continuously.

Prevention of air pollution in industrial premises by harmful substances consists of sealing equipment, using local and general supply and exhaust ventilation, streamlining the technological process, and preventing the formation of vacuum in workshops, especially in the winter and transition periods of the year. Vacuum promotes a more intense release of harmful substances (dust, vapors, gases) from the cracks of technological equipment.

The air temperature in the workroom depends mainly on production process. For example, heat sources in public catering establishments are stoves, boilers, steam pipelines, etc. In the warm season, warmth is also added solar radiation. Increased air temperature in the workroom causes rapid fatigue of workers, overheating of the body and excessive sweating. This leads to decreased attention, lethargy and can cause work-related injuries.

When performing heavy physical work in a room with a temperature of 30 ° C, desalting and dehydration of the body occurs, which can reach 10 - 12 liters per shift. Lack of water in the body causes thickening of the blood and disruption of the cardiovascular system, nutrition of tissues and organs. When determining workplaces for servicing technological processes, it should be borne in mind that the air temperature increases by 1. . . 2 C or more per meter of height and can reach 40 – 50  C. This must be taken into account when constructing work platforms for servicing large equipment.

The release of heat by the human body depends on the severity of the work performed. In this regard, all works are divided into three categories; light, medium and heavy.

		Characteristics of work	Energy consumption, Wh
I – light work		The work is carried out sitting, standing or involves walking, but does not require systematic physical exertion or lifting and carrying heavy objects.
II – moderately heavy work	Physical work performed standing or sitting, associated with constant walking, but not requiring the movement of heavy objects
	Physical work associated with constant walking and carrying light weights (up to 10 kg)
III – heavy work		The work involves systematic physical stress, as well as constant movement and carrying significant weights weighing more than 10 kg

Based on the amount of heat generation per 1 m 2 of area, production premises are divided into two categories; with minor (no more than 23.2 W/m2) and significant (more than 23.3 W/m2) excess heat.

One of the processes of adaptation to meteorological conditions is thermoregulation of the human body. Thermoregulation is the body's ability to regulate heat exchange with the external environment, while maintaining body temperature at a certain, constant level - an average of 36.6 °C.

Air humidity has a significant impact on the thermoregulation of the human body.

Any building, or industrial, needs high-quality air exchange. It will not only ensure the supply of oxygen, but also protect structures from the growth of mold and mildew, and provide comfortable living conditions for people. Today we will talk about what are the disadvantages and advantages ventilation systems. Types of ventilation, specifics of its design and useful recommendations– in our material today.

A fresh atmosphere in the room is a guarantee of excellent well-being for its inhabitants

Read in the article

Let's start with the basics: what is ventilation?

Ventilation is air exchange regulated using a complex special devices.

Doctors have found that an average healthy adult inhales about 20 thousand liters of air per day. In order for us to feel normal and be able to work effectively, the air must have a certain chemical composition, including ions, phytoncides and ozone levels.

Not always naturally air of this quality enters the premises. To establish this process, a ventilation system is used. It ensures the movement of air masses inside the room, their removal and removal of the exhaust atmosphere. The more intensively the room is used, the more powerful the ventilation system should be.

Classifications of ventilation systems according to various criteria

Air exchange systems are divided into different types on several grounds:

Classification sign	Subspecies
To organize the movement of air flows	Mechanical
To organize the movement of air flows	Natural
By functional purpose	Exhaust
	Supply
	Supply and exhaust
By service area	General exchange
By service area	Local
By design	Duct
By design	Ductless

Ventilation systems include a variety of equipment and can be combined with heating and noise reduction systems. For the air exchange process they use different kinds , thermal curtains, filters, noise silencers, air ducts, heaters, grilles different shapes and valves.

Let us consider the listed types of ventilation systems in more detail.

Basics of Natural Ventilation

Natural ventilation in the house is carried out due to different pressure and temperature conditions inside and outside, as well as with the help of winds blowing through the building.

As a rule, the temperature in the room is higher than outside, for this reason the exhaust air easily rises and leaves through the ventilation shafts, drawing in cooler masses outside.

In what cases is a ducted and ductless system used?

A ductless complex does not require a network of air ducts. Atmospheric exchange occurs through openings in the wall - supply and. Window windows, cracks under doors and transoms can serve as sources of fresh air. Ductless systems are suitable for living rooms. It is easy to install and does not require special maintenance or operating costs.

Duct ventilation requires an air duct. Its installation is justified if air intake or supply must be carried out in intensive mode and to a certain place in the room.

How to correctly design a ventilation system

Algorithm of main work:

need to study sanitary standards on air exchange in residential premises, correlate them with the dimensions of your rooms;
calculate the dimensions of air channels;
select the optimal layout of air ducts;
prepare sites for installation of structures;
install all system elements.

If you thought about high-quality air exchange at the stage of designing a house, you did the right thing. It is at this stage that you can plan the placement of communications so that they are not noticeable and at the same time work with maximum efficiency.

The main mistake in planning ventilation systems is installing too powerful networks, which will lead to unjustified energy losses. Another unpleasant moment is the occurrence reverse thrust in the ventilation of a private house.

Basics of calculating ventilation in a private house

You need to start designing a ventilation system by studying sanitary standards and correct calculation. To calculate natural ventilation, use the following sequence (all values are measured in cubic meters per hour):

In accordance with sanitary standards, the required volume of air entering the premises is determined.
Using the same criteria, the volumes of outgoing flow through the exhaust system are calculated.
The two obtained values are compared and the larger value is taken for further calculations.
Measure the height of the future common exhaust duct for natural ventilation.
Based on the number and productivity of ducts from each room in the house, the size of the common exhaust duct is calculated.

When calculating air exchange, you should take into account the operation of a mechanical hood in the kitchen. In addition, special attention should be paid to calculations for the bathroom, toilet and rooms without, such as the basement and boiler room.

To simplify calculations, you can use special calculators and programs. One of the most popular programs is Vent-Calc v2.0. How to work in it in several videos with detailed video instructions:

;

in living quarters that are separated from the room with ventilation by two doors;

on the second and subsequent floors - in corridors and halls.

It is permissible to install transfer valves from residential premises that do not have natural air exchange in rooms with ventilation.

Several ventilation system diagrams for example:

When planning ventilation ducts, it should be taken into account that their diameter cannot be less than 150 mm, and one side square pipe- less than 10 cm. Such a small air duct 3 meters long will provide an exhaust air of approximately 30 m 3 /hour.

Important! The length of all ventilation ducts on the floor must be the same, so the common air duct is placed in the center of the building.

Typically, the diameter of the air duct from the premises is made standard, and the intensity of air exchange is regulated by ventilation grilles with controlled blades.

If your house has only one floor, there is no need to install a common air duct in the center, as is done in multi-story structures. You can bring all the channels to the roof head.

Tips for arranging ventilation in a private home

Insulate ventilation ducts. Excessive cooling can lead to condensation. In winter this can lead to the formation of ice, in summer it can lead to the appearance of an unpleasant odor.
When planning the system, pay special attention to the aerodynamic characteristics of the air ducts. Do not try to make them too narrow; make sure that the diameter of the channel does not change along the entire length; the channels cannot be located horizontally.

Ensure the possibility of air exchange between living compartments using grilles and transfer valves. The area of such a valve is selected to be at least 200 cm².
In rooms without exhaust hoods, leave gaps under the doors of 1.5 - 2 centimeters.
To improve the operation of the ventilation system, install in wet areas blowers into air ducts. In the bathroom and toilet room can be mounted to these devices, then they will turn on only when a person is present.

To ensure natural ventilation in the kitchen, connect a tee to the kitchen hood with check valve. When the hood fan stops, the valve will open and provide natural air exchange.
If there is ground floor or basement, be sure to install ventilation ducts there. This way you will avoid dampness and preserve your floors.
To reduce energy losses, use humidity and temperature sensors in the natural ventilation system, complete with adjustable valves and.

Article

1. Ventilation

1.1 General information and purpose

For human life great importance has air quality. The well-being, performance, and ultimately health of a person depends on it. Air quality is determined by its chemical composition, physical properties, as well as the presence of foreign particles in it. Modern human living conditions require effective artificial means of improving the air environment. Ventilation technology serves this purpose.

In general, ventilation (from the Latin ventilatio - airing), according to the generally accepted definition, refers to the controlled air exchange in a room, as well as the devices that create it. The purpose of ventilation is to maintain chemical and physical condition air that meets hygienic requirements, i.e. ensuring certain meteorological parameters of the air environment and air purity. Factors whose harmful effects can be eliminated with the help of ventilation include: excess heat (convection, causing an increase in air temperature, and radiant); excess water vapor - moisture; gases and vapors chemical substances general toxic or irritant effect; toxic and non-toxic dust; radioactive substances.

1.2 General requirements and microclimate indicators

Sanitary rules establish hygienic requirements for the microclimate indicators of residential, public and industrial workplaces, taking into account the intensity of energy consumption of residents and workers, the time of work, periods of the year and contain requirements for methods of measuring and monitoring microclimatic conditions.

Microclimate indicators must ensure the preservation of the thermal balance of a person with the environment and the maintenance of an optimal or acceptable thermal state of the body. Indicators characterizing the indoor microclimate are:

Air temperature;

Surface temperature;

Relative humidity;

Air speed;

Intensity of thermal irradiation.

Particular attention is paid to production premises. Optimal microclimatic conditions are established according to the criteria of optimal thermal and functional state person. They provide a general and local feeling of thermal comfort during an 8-hour work shift with minimal stress on the thermoregulation mechanisms, do not cause deviations in health, and create the prerequisites for high level performance and are preferred in the workplace.

When designing, constructing and operating industrial premises, they are guided by sanitary rules, SanPiN 2.2.4.548-96 “Hygienic requirements for the microclimate of industrial premises”.

Optimal values of microclimate indicators must be observed at workplaces of industrial premises where operator-type work associated with nervous and emotional stress is performed (in cabins, at consoles and control stations for technological processes, in computer rooms, etc.). The list of other workplaces and types of work in which optimal microclimate values must be ensured is determined by the Sanitary Rules for individual industries and other documents agreed upon with the State Sanitary and Epidemiological Supervision authorities in the prescribed manner.

When designing buildings and structures in accordance with SNiP 41-01-2003, technical solutions should be provided that ensure:

a) standardized meteorological conditions and air purity in the service area of residential, public, and administrative buildings of enterprises;

b) standardized meteorological conditions and air purity in work area production, laboratory and warehouse premises in any buildings;

c) standardized levels of noise and vibration from the operation of equipment and heat supply systems, heating, ventilation and air conditioning, as well as from external sources noise. For emergency ventilation systems and systems smoke protection when working or testing in the premises where this equipment is installed, noise of no more than 110 dBA is allowed, and for impulse noise - no more than 125 dBA;

d) security atmospheric air from ventilation emissions of harmful substances;

e) maintainability of heating, ventilation and air conditioning systems

f) explosion and fire safety of heating, ventilation and air conditioning systems.

1.3 Classification of ventilation systems

With all the variety of ventilation systems, due to the purpose of the premises, the nature of the technological process, the type of harmful emissions, etc., they can be classified according to the following characteristic features: by the method of creating pressure to move air, by purpose, by service area and by design.

By method of movement ventilation is distinguished between the air removed from the premises and the air supplied to the premises natural(unorganized and organized) and mechanical (artificial) .

Unorganized natural ventilation refers to the air exchange in rooms that occurs under the influence of the difference in pressure between the external and internal air and the effects of wind through leaks in enclosing structures, as well as when opening vents, transoms and doors. Air exchange, which also occurs under the influence of the pressure difference between the external and internal air and the action of the wind, but through transoms specially arranged in the external fences, the degree of opening of which is regulated on each side of the building, is natural, but organized ventilation. This type of ventilation is called aeration.

Mechanical or artificial ventilation is the method of supplying air to or removing air from a room using a fan. This method of air exchange is more advanced, since the air supplied to the room can be specially prepared in terms of its purity, temperature and humidity.

Mechanically driven ventilation (mechanical ventilation) should be provided:

a) if meteorological conditions and air purity cannot be ensured by ventilation with natural impulse (natural ventilation);

b) for rooms and areas without natural ventilation.

Systems mechanical ventilation systems that automatically maintain indoor meteorological conditions at the specified level regardless of changing parameters of the external air environment are called air conditioning systems.

According to the method of organizing air exchange ventilation in rooms can be general exchange, local (localizing), mixed, emergency And smoke control . By purpose ventilation systems are divided into supply and exhaust. Ventilation systems that remove polluted air from a room are called exhaust. Ventilation systems that supply the room with outside air heated in cold period years are called inlet. Exhaust ventilation systems, depending on the place where harmful emissions are removed, and supply ventilation systems - from the place where outside air is supplied, are divided into general exchange, local and mixed.

General exchange ventilation is provided to create the same air conditions (temperature, humidity, air purity and air mobility) throughout the room, mainly in the work area. When any harmful substances are distributed throughout the entire volume of the room or it is not possible or impossible to catch them at the points of release. General ventilation can be like inlet, so exhaust, and more often supply and exhaust, providing organized air inflow and removal.

At local exhaust Ventilation removes contaminated air directly from the place where it is contaminated. Local supply ventilation is used in cases where Fresh air required only in certain areas of the premises (workplaces). An example of such ventilation is an air shower - a stream of air directed directly at the workplace.

Mixed systems, used mainly in industrial premises, are a combination of general ventilation with local ventilation.

Emergency ventilation units, according to SNiP 41-01-2003, they are installed in rooms in which there may be a sudden, unexpected release of harmful substances in quantities significantly exceeding the permissible ones. These settings are turned on only if it is necessary to quickly remove harmful emissions.

Anti-smoke ventilation is provided to ensure the evacuation of people from the premises of the building to initial stage fire.

The question of which of the listed ventilation systems should be installed is decided in each individual case, depending on the purpose of the room and the nature of the harmful emissions arising in it. And patterns of air flow inside the building.

Detailed information about technical solutions on the use of types of ventilation and the requirements for the design of ventilation systems can be found in SNiP 41-01-2003, clause 7.

1.4 Natural ventilation

Channel natural ventilation systems are systems in which the supply of outside air or the removal of contaminated air is carried out through special channels provided in the building structures, or attached air ducts. The air in these systems moves due to the difference in pressure between the external and internal air.

Ventilation should be understood as a whole complex of measures and units designed to ensure the required level of air exchange in serviced premises. That is main function of all ventilation systems is to support meteorological parameters on acceptable level. Any of the existing ventilation systems can be described according to four main characteristics: its purpose, the method of moving air masses, the service area and the main design features. And start studying existing systems follows with consideration of the purpose of ventilation.

Basic information about the purpose of air exchange

The main purpose of ventilation systems is to replace air in various rooms. In residential, domestic, business and industrial premises, the air is constantly polluted. Pollutants can be completely different: from almost harmless house dust before dangerous gases. In addition, it is “polluted” by moisture and excessive heat.

Four basic schemes for organizing air exchange during general ventilation: a – top to bottom, b – top to top, c – bottom to top, d – bottom to bottom.

It is important to study the purpose of air exchange systems and choose the most suitable one for specific conditions. If the choice is made incorrectly and there is not enough or too much ventilation, this will lead to equipment failure, damage to property in the room and, of course, will negatively affect human health.

Currently, there are quite a few different ventilation systems in their design, purpose and other features. Based on the method of air exchange, existing structures can be divided into supply and exhaust type structures. Depending on the service area, they are divided into local and general exchange. And according to their design features, ventilation units can be ductless or ducted.

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Purpose and main features of natural ventilation

Natural ventilation is installed in almost every residential and utility room. It is most often used in city apartments, cottages and other places where there is no need to install higher power ventilation systems. In such air exchange systems, air moves without the use of additional mechanisms. This happens under the influence of various factors:

Due to different air temperatures in and outside the serviced room.
Due to different pressures in the room served and the installation location of the corresponding exhaust device, which is usually located on the roof.
Under the influence of "wind" pressure.

Natural ventilation can be unorganized or organized. A feature of unorganized systems is that the replacement of old air with new occurs due to different pressures of external and internal air, as well as the action of wind. Air leaves and comes through the leaks and cracks of windows and door designs, as well as when opening them.

A feature of organized systems is that air exchange occurs due to the difference in pressure of air masses outside the room and in it, but in in this case For air exchange, appropriate openings are arranged with the ability to regulate the degree of opening. If necessary, the system is additionally equipped with a deflector designed to reduce pressure in the air channel.

The advantage of natural air exchange is that such systems are as simple as possible in development and installation, they have affordable price and do not require the use of additional devices or connection to the electrical network. But they can only be used where constant ventilation performance is not needed, because... the operation of such systems completely depends on various external factors such as temperature, wind speed, etc. Additionally, the possibility of using such systems is limited by the relatively low available pressure.

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Main features and purpose of mechanical air exchange

To operate such systems, special devices and equipment are used, thanks to which air can move over fairly long distances. Such systems are usually installed on production sites and other places where constant high-performance ventilation is required. Installing such a system at home is usually pointless. Such air exchange consumes quite a lot of electricity.

The great advantage of mechanical air exchange is that, thanks to it, it is possible to establish a constant autonomous supply and removal of air in the required volumes, regardless of external weather conditions.

Such air exchange is more effective than natural, also due to the fact that, if necessary, the supplied air can be pre-cleaned and brought to desired value humidity and temperature. Mechanical air exchange systems operate using various equipment and devices, such as electric motors, fans, dust collectors, noise suppressors, etc.

It is necessary to choose the most suitable type of air exchange for a particular room at the design stage. In this case, sanitary and hygienic standards and technical and economic requirements must be taken into account.

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Features of supply and exhaust systems

The purpose of exhaust and supply air exchange is clear from their names. Local supply ventilation is created for the influx clean air to the required places. It is usually preheated and cleaned. An exhaust system is needed to remove polluted air from certain places. An example of such air exchange is kitchen hood. It removes air from the most contaminated place - electrical or gas stove. Most often, such systems are organized on industrial sites.

Exhaust and supply systems are used in combination. Their performance must be balanced and adjusted taking into account the possibility of air flow into other adjacent rooms. In some situations, only an exhaust or only a supply air exchange system is installed. To supply clean air into the room from the outside, special openings are created or air supply equipment is installed. It is possible to organize a general exchange exhaust and supply ventilation, which will serve the entire room, and local, thanks to which the air in a specific place will change.

When organizing local system air will be removed from the most polluted places and supplied to certain specified areas. This allows you to establish air exchange most effectively.

Local supply ventilation systems are usually divided into air oases and souls. The function of the shower is to supply fresh air to work areas and reduce its temperature at the point of inflow. An air oasis should be understood as those areas of the serviced premises that are enclosed by partitions. They are supplied with cooled air.

In addition, as local supply ventilation, they can be installed air curtains. They allow you to create a kind of air partitions or change the direction of air flows.

The installation of local ventilation requires much less investment than the organization of general ventilation. At various types of production sites, in most cases, mixed air exchange is organized. Thus, to remove harmful emissions, general ventilation is established, and workplaces are maintained using local systems.

Appointment local exhaust system air exchange is the removal of emissions harmful to humans and mechanisms from specific areas of the room. Suitable for situations where the spread of such emissions throughout the entire space of the room is excluded.

In production premises, local exhaust ensures the capture and removal of various harmful substances. For this purpose, special suction is used. In addition to harmful impurities, exhaust ventilation units remove some of the heat generated during equipment operation.

Such air exchange systems are very effective because... make it possible to remove harmful substances directly from the place of their formation and prevent the spread of such substances throughout the surrounding space. But they are not without their drawbacks. For example, if harmful emissions are dispersed over a large volume or area, such a system will not be able to effectively remove them. In such situations, general exchange type ventilation systems are used.

Air exchange in rooms is one of the main requirements for organizing a normal microclimate, which must be maintained at all times. There are standards for this parameter depending on the purpose of the rooms. The standards stipulate how many times in a certain period of time the air should be completely changed. For example, air exchange should not be less than 12 m³/hour. That is, in one hour 12 m³ of air mass should be removed from the kitchen, and the same amount of fresh air should enter. All this can be provided by a ventilation system that is installed in. In this article we will consider types of ventilation, advantages and disadvantages of ventilation systems, as well as in which rooms which systems are best installed.

From the above, one can already imagine that ventilation is a set of special devices with the help of which air exchange is organized. And even ventilation can also be classified in this category. But let's take into account the fact that the question itself, what is ventilation, cannot determine the entire breadth of the topic we are studying. That is, one phrase that this is the organization of air exchange cannot be done. Because this is a diverse engineering network with its own specific nuances and requirements. Therefore, first of all, you need to understand the classification of ventilation systems.

Classification of ventilation systems

So, ventilation systems are divided according to different criteria:

by the method of air movement: natural ventilation and artificial;
according to its intended purpose, that is, where the pressure will be created: on the exhaust and supply;
according to zoning into local (local) and general.

You can also classify them according to the design features of the fans, but it’s better not to do this here. Because this is already a classification.

It is necessary to immediately make a reservation that, regardless of the rooms or buildings in which the ventilation system is organized, the equipment, devices and materials used in its design, as well as the diagrams, will be the same. But each variety has its pros and cons. Therefore, taking them into account, it is necessary to select the ventilation network for its operating conditions.

Natural ventilation system

Natural ventilation is based on the laws of physics. When warm air moves up, and cold moves down. Therefore, vertical channels are laid in buildings through which air moves. This is clearly seen in the example of apartment buildings in which ventilation shafts are constructed, penetrating the building from the basement to the roof. Channels connecting to the apartments are connected to this shaft.

Channels are usually installed in wet areas: kitchen, bathroom and toilet. They themselves are not visible, but they are always left on the walls under the ceiling as an entrance to the channel network. It is through them that the exhaust air will be removed to the street. But the ventilation itself will not work in just one ventilation shaft, because according to the laws of physics, how much air is removed, so much of it must enter.

Therefore, it is necessary to organize the influx of air masses. Previously, they did not think about this, because they provided the required influx. Today, with the installation of sealed structures in the form plastic windows and sealed doors created an inflow problem. Or rather, its complete absence. This means that there is no air exchange in such houses and apartments.

Engineering thought has solved this problem from different positions. For example, special devices or with duct valves inserted into the walls. There are many options offered today, all of them are effective and efficient.

Natural ventilation in a private house is easier to organize. Especially air valves. There are two types of them: supply and exhaust. The first ones are installed under the window sills above, through which fresh air will penetrate into the rooms. By the way, the place was chosen specifically so that the cold air would be immediately warmed by heating. The second ones are mounted under the ceiling on the opposite wall from the supply models. You can organize the flow of air masses in this way. This is when supply valves are installed in one room, and exhaust valves in another.

Now regarding the advantages and disadvantages of natural ventilation. She has one big advantage - minimum costs for construction and no operating costs. And one big minus is complete dependence on climatic conditions. If the temperature outside is higher than the temperature inside the house, then the laws of physics begin to operate in the opposite direction, that is, from the street to the premises. In strong winds, ventilation works more efficiently than in calm conditions.

Forced (mechanical) system

Forced ventilation in a private house is a system in which it is installed. Additionally, filters, heating units, etc. can be used, with the help of which the quality of the supply air is improved. Everything else is the same pipe wiring according to the same pattern as natural.

Main components of supply and exhaust ventilation

Supply and exhaust ventilation belong to the category of forced systems. From the names it becomes clear where the fan should be installed. In the first case, on the supply ducts, in the second, on the exhaust ducts.

Supply circuit

The simplest setting that determines is duct fan, it is installed inside the wall near the floor or above heating radiators. By appearance This is the pipe in which the fan is mounted. A hole is made in the wall with a diameter equal to the outer diameter of the fan unit, where it is inserted. The device is closed on both sides with decorative grilles and connected to an alternating current network of 220 volts via.

For small private houses this is perfect option. Moreover, there is always the opportunity, by choosing the right channel device, to organize a flow through several rooms. In this case, it is better to install it yourself in a service room. This scheme will work normally if the cross-section of the exhaust duct matches the fan power. Therefore, it is very important to correctly calculate ventilation in a private house.

Exhaust ventilation

The simplest one in this group is natural system, in which a fan unit is installed on the exhaust duct. For example, this could be a rooftop installation, as shown in the photo below.

You can again use duct devices by installing them under the ceiling. By the way, it is also part of the mechanical ventilation system.

Supply and exhaust ventilation

From the name itself it becomes clear that this is a symbiosis of the two previous schemes. The only difference is the operation of one or two fans, which are enclosed in one housing, both for exhaust and for supply. For obvious reasons, the device itself will not be able to provide air exchange, so air ducts with diffusers are scattered from it throughout the rooms, through some the air is supplied to the house, through others it is pumped out.

In this case, air mass distribution schemes can be of two types:

The air is supplied to the living quarters and is discharged through the service rooms through the overflow method: kitchen, toilet and bathroom. In this case, supply diffusers are installed under the ceiling.
The influent masses are supplied from below near the floor and immediately removed into the room through exhaust openings located on the ceiling.

Both options are expensive in terms of a large number of air ducts, which will have to be placed strictly according to a pre-planned pattern. In this case, the scheme may turn out to be quite complex and branched. Therefore, supply and exhaust ventilation is considered the most difficult in terms of installation. By the way, the first option is called the removal method, the second is the mixing method.

Pros and cons of different types of ventilation systems

Of all the above-described systems, the supply and exhaust system is the most complex and costly in terms of capital investments. Although today monoblock models have appeared on the market, with the help of which some aspects, namely installation and operation, have become easier. But this type of ventilation provides maximum efficiency air exchange, plus air purity.

In this case, the air coming from the street will be heated by the air coming out of the rooms. That is, inside the fan unit there are pipes mating in planes. One of them moves air into the street, the other from the street. It is through the interface plane that the temperature exchange occurs. Heating is important aspect increasing comfort inside the rooms of a private house. This method is called recovery.

As for individually exhaust ventilation in a private house and a supply room, then they have no strong differences from each other. The only thing that can be noted is the fact that the natural ventilation system can be easily converted into a forced exhaust type by installing a fan in the ventilation shaft. This will not work with forced.

How to calculate ventilation in a private house

An indicator such as the air exchange rate is used. It was already mentioned at the beginning of the article. This parameter is recorded by SNiP under number 2.08.01-89* under the name “Residential buildings”. So in Appendix No. 4 there is a table in which the air exchange rate is shown depending on the purpose of the room. We will not rewrite the entire table; we will indicate the main premises:

Room	Air exchange rate
Residential	3 m³/hour for each square meter area with a ceiling height of 3 m
Kitchen with electric stove	60 m³/hour
Kitchen with gas stove: 2 burners 3 burners 4 burners	60 m³/hour
Bathroom	25
Toilet	25
Combined bathroom	50

Now, as for the calculation. The formula used for this is:

N= V x L , Where

N – ventilation performance,
V - volume of the room,
L — frequency of air exchange.

Pay attention to the multiplicity in residential areas. In principle, it turns out that it is equal to “1”. That is, in one hour the volume of air in them should change completely. This means that the ventilation performance should be equal to the volume of the room.

But this is just a calculation that is based on standards. The ventilation system itself consists of air ducts, which must provide the necessary permeability of air masses. Therefore, there are rules here too. Eg, round pipe with a diameter of 150 mm, and this cross-section equal to 0.016 m³, provides a throughput of 30 m³/hour. The same parameter supports air duct rectangular section 100×100 mm. At the same time, such a volume is supported by a riser height of 3 m. That is, if this value is less, productivity will decrease accordingly.

Attention! If several exhaust ducts are installed in a house, then their diameter and length must be the same.

Calculation example. Input data:

total area of residential premises – 60 m²;
The kitchen has a 4-burner gas stove;
toilet and bathroom are separate;
ceiling height – 3 m;
inflow from living quarters, exhaust from the kitchen, bathroom and toilet.

First of all, the volume of supply air is calculated. It is equal to the volume of residential premises: 60 × 3 = 180 m³/h . Now we need to calculate the volume of exhaust air. Here you will have to refer to the table:

in the kitchen this figure is 90 m³/h,
25 in the toilet and bathroom.

In general it turns out: 90 + 25 + 25 = 140 m³/h . Now the two obtained values must be compared. It is clear that 180 is greater than 140. This means that the performance of the ventilation system in this particular case will be 180 m³/hour.

This calculation is valid for both natural and mechanical ventilation.

Ventilation arrangement in a private house

The question of how to properly install ventilation in a private home mainly concerns the choice of the type of system. That is, whether it will be natural or forced. In this regard, experts say only one thing - if the house is small and is being built in an ecologically clean area, then the natural option will be just right.

The main task of design and construction is to prevent the formation of reverse draft in the ventilation of a private house. That is, so that the outflow of air occurs from the premises to the street, and not vice versa. This sometimes happens if the house is installed, which means temperature regime in summer indoors is low compared to outdoors.

If the house large sizes into several rooms, then you need to use a forced circuit and preferably a supply and exhaust system. Because this is the only way to ensure volumetric air circulation.

Scheme of a ventilation system in a private house

Designing a ventilation system is one of the rules that must be adhered to. You can draw a diagram of the ventilation system of a private house on paper with your own hands. What is important here is schematic design, not precise calculations with verified dimensions of the air ducts.

In this case, it is necessary to take into account several important points:

The most polluted rooms in terms of air should be located at the end of the schematic chain. These are the kitchen, bathroom and toilet.
The outlet openings should be located in a convenient location to allow for laying the shaft.
Supply channels are located in residential premises.

Air ducts for ventilation

Air ducts are transport arteries through which air masses move. The effectiveness of their work depends on three criteria:

form,
section,
the material from which they were made.

The cross-sectional shape is round or rectangular. The first ones allow air to pass through them better, the second ones are easier to install. By material - metal or plastic. The former are most often used in industrial premises. They can easily withstand different loads. The latter are more often used in everyday life. It should be noted that plastic air ducts for ventilation - there is a wide variety of types and sizes.

Plastic pipes are made from PVC, fluoroplastic, polypropylene and polyethylene low pressure. The last position is flexible, so such air ducts are often used for complex wiring.

Attention! Today, except for air ducts round section Manufacturers also offer rectangular plastic pipes. They are most often used if it is necessary to carry out open wiring, but at the same time make sure that the air ducts are not visible.

Let us add that ventilation in a private house from plastic pipes is a list of the following advantages.

Standard sizes: diameter – 100÷200 mm, for rectangular ones, width 100 to 200 mm, height from 50 to 200 mm. All parameters comply with the standards.
Low specific gravity, which allows for simple fastening.
Easy to install.
Smooth inner surface, which reduces the possibility of debris accumulation.
Long-term operation.

Fans for forced circuit

To device forced ventilation in a private house one must approach from the position of accurate calculation and the right choice fan And you need to choose it based on its design features and performance. The second criterion was dealt with when we considered the rules for calculating the ventilation system. As for designs, there are three of them:

axial models,
centrifugal,
duct.

The first are wall or window devices that are installed from inside the premises. They small sizes and power, but are effective for providing air exchange in small private houses.

The second are powerful installations, which are often called “snails”. In private houses they are installed only if it is necessary to ensure the outflow of a large volume of air masses from one place.

Still others are also household ones. They have already been mentioned above. These are cylindrical devices that are installed in through hole made in the wall.