How is the calculation of the ventilation system indoors. Calculation of the local ventilation exhaust system How to calculate air flow for local ventilation

A favorable indoor microclimate is an important condition for human life. Its in the aggregate determine the temperature, humidity and air mobility. Deviations of parameters negatively affect health and well-being, cause overheating or supercooling of the body. The lack of oxygen leads to the hypoxia of the brain and other organs.

Source vglazkov.com.

Calculation and regulations

The calculation of the ventilation of the room is carried out when designing an object according to SNiP 13330.2012, 41-01-2003, 2.08.01-89. But there are cases when her work is ineffective. If the check of traction with paper stripes or flame lighters did not reveal the violation of ventilation violations, it means that exhaust ventilation does not cope with its functions due to the incorrectly selected section.

What is the ventilation

The task of ventilation is to provide the necessary air exchange indoor, create optimal or acceptable conditions for a long residence of a person.

Studies have established that 80% of time people are carried out in the premises. In one hour in a calm state, a person allocates 100 kcal to the environment. The heat transfer occurs convection, radiation and evaporation. With not enough movable air, energy transfer from the surface of the skin into space slows down. As a result, many functions of the body suffer, a number of diseases arise.

Source yandex.ru.

Lack of or insufficient ventilation, especially in rooms with high humidity, leads to stagnant phenomena. They are accompanied by the invasion of labor-based mold fungi, unpleasant smells and constant dampness. The moisture is adversely affected by building structures, leads to the rotting of wooden and corrosion of metal elements.

With excessive traction, the output of air masses increases in the atmosphere, which in winter leads to the loss of a large amount of heat. Growing the cost of heating at home.

The quality and purity of air is the main factor that determines the effectiveness of ventilation. Contaminating evaporation from building materials, furniture, dust and carbon dioxide must be removed in a timely manner.

There is a reverse situation when the air in the house or apartment is much cleaner than on the street. Exhaust gases on a lively track, smoke or soot, poisonous contaminants of industrial enterprises are able to poison the atmosphere indoors. For example, in the center of the large city, carbon monoxide content is 4-6 times, nitrogen dioxide is 3-40 times, sulfur gas is 2-10 times higher than in rural areas.

The calculation of the ventilation is produced to determine the type of air exchange system, its parameters in which the energy efficiency of housing and a favorable microclimate in the premises will be combined.

Microclimate parameters for calculation

Standards according to GOST 30494-2011 determine the optimal and permissible air quality parameters in accordance with the purpose of the premises. They are classified by standards for the first and second category. These are places where people relax in the lying position or sitting, studying, mental labor.

Depending on the period of the year and the purpose of the premises, the optimal and permissible temperature of 17-27 ° C are installed, the relative humidity of 30-60% and air velocity is 0.15-0.30 m / s.

Source Remontik.org.

In residential premises, when calculating ventilation, the necessary air exchange is determined using specific norms, in production - according to the permissible concentration of pollutants. The amount of carbon dioxide in the air should not exceed 400-600 cm³ / m³.

On our site you can find contact with the construction companies that offer an internal redevelopment service. Directly to communicate with representatives, you can visiting the exhibition of houses "Low-rise country".

Types of ventilation systems according to the method of creating thrust

The movement of the air masses arises as a result of the pressure difference between air layers. The greater the gradient, the stronger the prompting force. To create it, a natural, forced or combined ventilation system is used, where supply, exhaust or recycling (mixed) methods are used. In industrial and public buildings, emergency and copyright ventilation are provided.

Natural ventilation

Natural ventilation of the premises occurs according to physical laws - due to the difference in temperatures and pressures between the outer and the inner air. In the days of the Roman Empire, the engineers were installed in homes for the likeness of mines that served to ventilate.

The complex of natural ventilation includes external and internal openings, fraamuga, vents, wall and window valves, exhaust mines, ventilation, deflectors.

Source Rumahku.com.

The quality of ventilation depends on the volume of the passing air masses and the trajectories of their movement. The most favorable option is when the windows and doors are located in opposite ends of the room. In this case, when circulating air, it is full of its replacement throughout the room.

Exhaust channels are placed in rooms with the highest levels of pollution, unpleasant odors and humidity - kitchens, bathrooms. Trying air comes from other rooms and squeezes the street worked out.

In order for the extractor to work in the right mode, its top should be above the roof of the house by 0.5-1 m. It creates the necessary pressure difference to move the air.

Natural ventilation is silent, does not consume electricity, does not require large investments on the device. Air masses penetrating from outside do not acquire additional properties - do not heated, not cleared and not moisturized.

Air recycling is limited to the limits of one apartment. From the neighboring premises of the supply should not be.

Forced ventilation began to be used from the mid-19th century. First, large fans were used on mines, in the trums of ships, drying shops. With the advent of electrical engines in the ventilation of the premises, a revolution occurred. Adjustable devices appeared not only for industrial, but also for household needs.

Source stroy-podskazka.ru.

Now the outer air during passage through the system of forced ventilation is reported additional valuable qualities - it is purified, moisturized or dried, ionized, heated or cooled.

Fans and ejectors move large volumes of air masses on significant areas. The system includes electric motors, dust collectors, heaters, silencers, control and automation devices. They are embedded in air duct channels.

Video Description

More information about the calculation of ventilation with the recuperator is told in this video:

Calculation of natural ventilation of residential premises

The calculation is to determine the flow of supply air L in the cold and warm period of the year. Knowing this magnitude, you can find the area of \u200b\u200bthe cross section of the air ducts.

The house or apartment is considered as a single air volume, where the circulation of gases occurs through open doors or curved by 2 cm from the floor of the canvas.

The inflow occurs through the leakage windows, external fences and by venting, removal - through exhaust ventilation.

Source market.sakh.com.

The volume is found in three methods - multiplicity, sanitary standards and square. From the obtained values \u200b\u200bchoose the greatest. Before calculating ventilation, determine the purpose and characteristics of all rooms.

Basic formula for the first calculation:

L \u003d nxv, m³ / h, where

V - the size of the room (the product of the height of the square),
n is the multiplicity determined by SNiP 2.08.01-89 depending on the calculated temperature in the room in the winter period.

According to the second procedure, the volume is calculated on the basis of the specific rate per person regulated by SNiP 41-01-2003. Considate the number of permanent people, the presence of a gas stove and a bathroom. By tab.m1 consumption 60 m³ / person per hour.

Third way - in the area.

A - area of \u200b\u200bthe room, m²,
k is a regulatory consumption on m².

Calculation of the ventilation system: example

Three-room house with a total area of \u200b\u200b80 m². The height of the room is 2.7 m. Lives three people.

Living room 25 m²,
bedroom 15 m²,
bedroom 17 m²,
bathroom - 1,4² m²,
bath - 2.6 m²,
kitchen 14 m² with four-componuous stove,
corridor 5 m².

Separately find consumption on the influx and exhaust so that the amount of incoming air is equal to removable.

living room L \u003d 25x3 \u003d 75m³ / h, multiplicity for SNiP.
bedrooms L \u003d 32x1 \u003d 32 m³ / h.

Total flow rate:

L SURE \u003d LG. + LSPAL. \u003d 75 + 32 \u003d 107 m³ / h.

bathroom L \u003d 50 m³ / hour (tab. Snipe 41-01-2003),
bath L \u003d 25 m³ / hour.
kitchen L \u003d 90 m³ / hour.

The corridor on the influx is not normalized.

On hood:

L \u003d LDK. + Lsanuz. + L Baths \u003d 90 + 50 + 25 \u003d 165 m³ / h.

Tracting consumption less exhaust. For further calculations, the highest value of L \u003d 165 m³ / h is adopted.

According to sanitary standards, the calculation is carried out on the basis of the number of tenants. The specific consumption per person is 60 m³.

L Society. \u003d 60x3 \u003d 180m / h.

Taking into account temporary visitors for which the established air flow 20m / h can be taken by L \u003d 200 m³ / h.

By area, consumption is determined, taking into account the regulatory speed of air exchange 3m² / hour per 1 m² of dwelling.

L \u003d 57x3 \u003d 171 m³ / h.

According to the results of the calculations, consumption under the sanitary standards of 200 m³ / h, the multiplicity of 165 m³ / h, in the area of \u200b\u200b171 m³ / h. Although all options are correct, the first for living conditions will be more comfortable.

Outcome

Knowing the air balance of a residential building, choose the size of the section of the air ducts. Most often use rectangular channels with the aspect ratio of 3: 1 or round.

Source SustaintRust.org.nz.

For a convenient calculation of the section, you can use the online calculator or diagram where the speed and air flow is taken into account.

When ventilating with natural motion, the speed in the trunk and branched air ducts takes equal to 1 m / h. In the forced system 5 and 3 m / h, respectively.

With the required air exchange 200 m / h, it suffices to perform a natural ventilation system. With large volumes of moved air, mixed recycling is used. In channels, the devices calculated by productivity, which provide the necessary microclimate parameters.

The task of an organized air exchange room of a residential building or an apartment is to bring extra moisture and spent gases, enclosing fresh air. Accordingly, for the exhaust device and the influx, it is necessary to determine the amount of air mass removed - perform the calculation of ventilation separately for each room. Methods of calculations and air flow rates are accepted exclusively on SNiP.

Sanitary requirements for regulatory documents

The minimum amount of air supplied and removed from the cottage room by the ventilation system is regulated by two main documents:

"Buildings Residential Multi-Fire" - SNiP 31-01-2003, paragraph 9.
"Heating, ventilation and air conditioning" - SP 60.13330.2012, mandatory application "K".

In the first document, sanitary and hygienic requirements for air exchange in residential premises of apartment buildings are presented. This data must be based on the calculation of ventilation. 2 types of dimension are used - air consumption by volume per unit of time (m³ / h) and hour more.

Reference. The multiplicity of the air exchange is expressed by a number indicating how many times the air room is completely updated for 1 hour.

Carrying - Primitive Method for Oxygen Update Residence

Depending on the purpose of the room, the supply and exhaust ventilation must ensure the following consumption or the number of air mixture updates (multiplicity):

living room, children's bedroom - 1 time per hour;
kitchen with electric stove - 60 m³ / h;
bathroom, bathroom, toilet - 25 m³ / h;
for and kitchen with a gas stove requires multiplicity 1 plus 100 m³ / h during equipment operation;
, burning natural gas, is a three-time update plus air volume required for combustion;
storeroom, dressing room and other utility rooms - multiplicity 0.2;
drying or post-90 m³ / h;
the library, the office is 0.5 times within an hour.

Note. Sniped provides for a reduction in the load on general ventilation with non-working equipment or the absence of people. In residential premises, multiplicity decreases to 0.2, technical - up to 0.5. The consurance of the rooms where gas-wide installations are located, - the hourly one-time update of the air.

Emissions of harmful gases due to natural traction - the cheapest and easiest way to update air

In clause 9 of the document implies that the exhaust volume is equal to the value of the inflow. The requirements of the SP 60.13330.2012 are somewhat easier and depend on the number of people located in the room 2 hours or more:

If 1 living accounts for 20 m² and more than the area of \u200b\u200bthe apartment, the room is provided with a fresh influx in a volume of 30 m³ / h per 1 person.
The volume of the supply air is considered in the area, when 1 tenant accounts for less than 20 squares. The ratio is: 3 m³ of tributary is supplied to 1 m² of housing.
If there is no ventilation in the apartment (there are no windows and opening windows), for each living, it is necessary to submit 60 m³ / h of a clean mixture regardless of the quadrature.

The listed regulatory requirements of two different documents do not contradict each other at all. Initially, the performance of the ventilation community system is calculated by SNiP 31-01-2003 "Residential buildings".

The results are checked with the requirements of the Ventilation and Air Conditioning Rules and, if necessary, are adjusted. Below we will analyze the calculated algorithm on the example of a one-storey house shown in the drawing.

Determination of air flow rate

This typical calculation of the supply and exhaust ventilation is performed separately for each apartment room or a country cottage. To find out the consumption of air masses on the building as a whole, the results obtained are summed up. Pretty simple formula is used:

Decoding designations:

L is the desired volume of supply and exhaust air, m³ / h;
S - square room where ventilation is calculated, m²;
h - the height of the ceilings, m;
n is the number of rooms of the room air environment for 1 hour (it is regulated by SNiP).

Example of calculation. The living room area of \u200b\u200ba single-storey building with a height of the ceilings 3 m is 15.75 m². According to the prescriptions of SNiP 31-01-2003, the multiplicity N for residential premises is one. Then the hour consumption of the air mixture will be L \u003d 15.75 x 3 x 1 \u003d 47.25 m³ / h.

Important moment. Determining the volume of the air mixture removed from the kitchen with the gas stove depends on the ventilation equipment installed. The common scheme looks like this: a single exchange according to the standards provides a system of natural ventilation, and additional 100 m³ / h drops the household.

Similar calculations are made in all other rooms, the diagram of the organization of the air exchange (natural or forced) is developed and the dimensions of the ventilation channels are determined (see the example below). Automate and speed up the process will help the estimated program.

Online calculator to help

The program considers the required amount of air to the multiplicity regulated by SNiP. Simply select a variety of rooms and enter its dimensions.

Performance of a system serving up to 4 rooms.
Dimensions of air ducts and air distribution grids.
Resistance to the aircraft network.
Power of the carrier and indicative costs of electricity (when using an electric canifice).

If you need to choose a model with moisture, cooling or recuperation - use the Calculator on the Breezart website.

Example of calculating ventilation using the calculator

In this example, we will show how to calculate the supply ventilation for a 3-bedroom apartment in which a family of three (two adults and a child) lives. In the afternoon, relatives come to them sometimes, so there can be up to 5 people in the living room for a long time. The height of the apartment ceilings is 2.8 meters. Parameters of premises:

The cost of the flow rate for the bedroom and children will set in accordance with the recommendations of SNiP - 60 m³ / h per person. For the living room, it is limited to 30 m³ / h, because a large number of people in this room happens infrequently. By SNIP, such an air consumption is allowed for premises with natural ventilation (you can open a window for aircraft). If we and the living room were set up the air flow rate of 60 m³ / h per person, the required performance for this room would be 300 m³ / h. The cost of electricity for heating of such a number of air would be very high, so we made a compromise between comfort and economy. To calculate air exchange by multiplicity for all rooms, we choose a comfortable double air exchange.

The main air duct will be rectangular hard, branch - flexible insulated (such a combination of type of air ducts is not the most common, but we chose it for demonstration purposes). For additional cleaning of the supply air, a coal-dust filter of thin cleaning of the EU5 class (calculation of the resistance of the network will be conducted with contaminated filters). Air velocities in the air ducts and the permissible level of noise on the lattices will leave equal to the recommended values \u200b\u200bthat are specified by default.

Calculation Let's start with the preparation of the air distribution network scheme. This scheme will allow us to determine the length of the air ducts and the number of turns that can be both in the horizontal and vertical plane (we need to count all the turns at right angles). So, our scheme:

The resistance of the air distribution network is equal to the resistance of the longest plot. This plot can be divided into two parts: the main air duct and the longest branch. If you have two branches of approximately the same length, then you need to determine which of them has greater resistance. To do this, it can be taken that the resistance of one turn is equal to the resistance of 2.5 meters of the duct, then the greatest resistance will have a branch, which has a value (2.5 * of turns + duct length) maximum. It is necessary to allocate two parts from the track so that you can set different types of air ducts and different air velocity for the main plot and branches.

In our system, all branches are installed balancing throttle valves, allowing you to customize air costs in each room in accordance with the project. Their resistance (in the open state) is already taken into account, since this is a standard element of the ventilation system.

The length of the main air duct (from the air intake lattice to the branch to room No. 1) - 15 meters, on this site there are 4 turn at right angles. The length of the supply installation and the air filter can be not taken into account (their resistance will be taken into account separately), and the resistance of the noisemaker can be taken with equal resistance of the air duct of the same length, that is, simply consider it part of the main air duct. The length of the longest branch is 7 meters, it has 3 turns at right angles (one - at the point of branch, one in the air duct and one in the adapter). Thus, we asked all the necessary source data and now we can start calculations (screenshot). The calculation results are reduced to the table:

Premises calculation results

The results of the calculation of general parameters

Type of Ventsystem	Normal	Vav.
Performance	365 m³ / h	243 m³ / h
Size section of the main air duct	253 cm²	169 cm²
Recommended sizes of the main air duct	160x160 mm 90x315 mm 125x250 mm	125x140 mm 90x200 mm 140x140 mm
Resistance to the aircraft network	219 PA	228 PA
Power of the Calrifer	5.40 kW	3.59 kW
Recommended supply installation	Breezart 550 LUX (in the configuration by 550 m³ / h)	Breezart 550 LUX (VAV)
Maximum performance Recommended Pu	438 m³ / h	433 m³ / h
Power electric. Calrifra Pu	4.8 kW	4.8 kW
Mid-average electricity costs	2698 rubles	1619 rubles

Calculation of the aircraft network

For each room (subsection 1.2), the performance is calculated, the air duct section is determined and a suitable duct of standard diameter is selected. According to the Arktos catalog, the sizes of switchgear with a specified noise level are determined (data for the AMN, ADN, AMR, ADR series) is used. You can use other lattices with the same dimensions - in this case it is possible a slight change in the noise level and resistance to the network. In our case, the grilles for all rooms were the same, since at noise level of 25 dB (a), the permissible air flow through them is 180 m³ / h (smaller lattices in these series).
The sum of air expenditures for all three rooms gives us the overall performance of the system (subsection 1.3). When using the VAV system, the system performance will be by a third lower due to the separation adjustment of air flow in each room. Next, the cross section of the main duct is calculated (in the right column - for the VAV system) and the suitable ducts of rectangular section are selected (several options are usually given with different aspect ratios). At the end of the section, the resistance of the aircraft network is calculated, which turned out to be very large - this is due to the use of a fine cleaning filter in the ventilation system, which has high resistance.
We received all the necessary data for the configuration of the air distribution network, with the exception of the size of the main air duct between the branches 1 and 3 (this parameter is not calculated in the calculator, since the network configuration is unknown in advance). However, the area of \u200b\u200bthis section can be easily calculated manually: from the cross-sectional area of \u200b\u200bthe main air duct you need to subtract the cross section of the branch number 3. After receiving the area of \u200b\u200bthe duct cross section, its size can be determined by software.

Calculation of the power of the carrier and selection of the supply installation

The recommended BreeZart 550 LUX model has programmatically customizable parameters (Productivity and Power of the COLIONTER), so the performance is indicated in brackets to be selected when setting up PU. It can be noted that the maximum possible power of the carrier of this PU is 11% lower than the calculated value. Lack of power will be noticeable only at an outdoor temperature below -22 ° C, and this happens not often. In such cases, the supply unit will automatically switch to a smaller speed to maintain a given temperature at the output (Comfort function).

In the results of the calculation, in addition to the required performance of the ventilation system, the maximum performance PU is indicated at a given network resistance. If this performance turns out to be noticeably higher than the desired value, you can use the feature of the software limit of maximum performance, which is available for all Breezart junctions. For the VAV system, the maximum performance is indicated for reference, since the adjustment of its performance is automatically produced during the system.

Calculation of the cost of operation

This section calculates the cost of electricity spent on air heating during the cold period of the year. Costs for the VAV system depend on its configuration and operation mode, therefore it is accepted with equal average value: 60% of the costs of a conventional ventilation system. In our case, you can save the reducing air flow at night in the living room, and in the afternoon - in the bedroom.

The task of the ventilation system of the residential building is a conclusion from the premises of the exhaust gases, excess moisture and input of pure fresh air. In order for the air exchange in the building as efficiently as possible, the ventilation is calculated individually before its arrangement for each room, utility rooms, basement. Air consumption standards, calculation methods are taken strictly by SNiP.

Sanitary requirements

To calculate the air volume for ventilation, which it must submit to the room and vice versa, to delete from it, you need to familiarize yourself with the requirements of SNiP 31-01-2003 and SP 60.13330.2012. The first document establishes sanitary requirements for ventilation systems of residential buildings.

Two types of parameters are taken to calculate the SNIP: the consumption of air volume per unit of time (cubic meters per hour) and hourly (how many times for one hour passes the full cycle of air exchange in the room). These parameters depends on the purpose of the room:

When the equipment and the absence of people indoors, the SNOP is provided to reduce the load on ventilation. For example, hourly is reduced to the coefficient of 0.2 in residential rooms and up to 0.5 in the technical premises. The exceptions are the premises in which gas equipment is installed. According to SNOP, the exhaust volume should be equal to the volume of the inflow.

Ventilation requirements for SP 60.13330.2012 is much easier. The parameters of the required air exchange depends on the number of people, indoors for more than two hours:

Despite the fact that the requirements for regulatory documents are somewhat different, they do not contradict each other. Preliminary calculations are performed according to the standp standards. The results obtained are checked with the requirements of the joint venture. If necessary, the parameters are proof.

Factors affecting the quality of air exchange

The quality of the operation of the ventilation system depends on the pollution of the air environment. In the premises of various purposes in the air, various harmful components can be concentrated:

humidity;
elements of exhaust gases;
human discharge (breathing, sweat and other);
evaporation of harmful substances;
heat energy from working installations.

In industrial facilities, the simultaneous presence of several listed pollution is possible. Therefore, when you calculate the load of ventilation at such objects, all factors are taken into account.

5 factors when planning and installation of ventilation. What should be taken into account when preparing ventilation?

Purpose of supply and exhaust ventilation:

cleaning of exhaust air indoors;
removal from the air of harmful components and extra moisture;
absorption of excess thermal energy, temperature regime settlement;
feed to the room of fresh air, its cooling or heating.

To perform listed functions, ventilation must have sufficient power. Therefore, before equipping air exchange, it is necessary to make the calculation of the parameters and correctly select ventilation equipment.

Premises formula:

Lots \u003d 3600 * f * Wo, where:

F is the total area of \u200b\u200bopenings (sq. M).
WC is the average (the parameter depends on air pollution and directly from the operation being performed).

The power of the ventilation system also affects the heating of clean air. To reduce costs, the recycling method is applied - part of the air medium taken from the room is cleaned and fed. In this case, fresh air closed from the street should be at least 10% of the total supplied air mass, and the purified air from the room should not contain more than 30% of harmful components.

It is strictly forbidden to use a method for recycling on industrial facilities, where harmful substances 1-3 of the hazard class, explosive components are concentrated in the air.

Exhaust system

Before the calculation of exhaust ventilation should carefully examine the requirements of regulatory documents. According to SNiP, the required amount of clean air depends on human activity:

20 cubic m. / hour - with low activity;
40 cubic. m. / hour - with medium;
60 cubic. m. / hour - with high.

Next, you need to consider the number of people in the same room and the volume of the building. And also you need to know in one hour. For sleeping rooms, its indicator is 1 (single), for household - 2 (double), for kitchen, toilet, bathroom, pantry - 3 (three-time).

An example of calculating the ventilation system for household rooms with an area of \u200b\u200b20 square meters. m, the ceiling height is 2.5 m, in which 2 people are constantly with medium activity:

V \u003d S x N, where V is the volume of the room, S is the area, H is height.
V \u003d 20 x 2,5 \u003d 50 cubic meters. m.
The multiplicity rate is 2, the average activity is 40 cu. m / h per person.
Ventilation performance by multiplicity - V x 2 \u003d 100 cubic meters. m. / h
Performance of people's activity - 40 x 2 \u003d 80 cubic meters. m. / h

How to make ventilation in a private house? Selection and calculation. Hood in the house. Air duct for ventilation

From the obtained values \u200b\u200bfor two options for calculation is taken more, that is, 100 m 3 / h. Similarly, the ventilation system of the entire residential building is calculated.

Secretary ventilation

Secondary type ventilation systems are used in large industrial facilities. Systems circulate air flow throughout the production room or more of it. Their work does not depend on natural factors, in addition, ventilation systems are capable of moving large volumes of air for long distances through the air ducts.

The air exchange for generally exchange systems is determined depending on the method of removing excess thermal energy from the room and dilute of the waste air environment, which contains harmful components, a clean air flow to admitted concentration documents.

The required volume of the supply air for the overturning of excess thermal energy is calculated by the formula:

L 1 \u003d Qola. / C * R * (T UD. - T PR.), Where

Qizb (kJ / h) is an overweight thermal energy.
C (J / kg * k) - air heat capacity (constant value \u003d 1.2 J / kg * K).
R (kg / m 3) - air density.
T UD. (ºС) -.
T Ave. (ºС) - the temperature of fresh air taken from the street.

The temperature of the external environment depends on the time of year and the geographical location of the industrial facility. The temperature of the exhaust air medium in the workshop is usually taken above 5 ºС from the external temperature. Air density is equal to 1.225 kg / cubic meters.

To calculate the ventilation in the room, it is necessary to calculate the required amount of supply air, to reduce the concentration of harmful substances in the air mixture to the established norms. This parameter is calculated by the following formula:

L \u003d G / G Ud. - g, where

G (mg / h) - the number of harmful elements allocated.
G Ud. (mg / m 3) is the concentration of harmful components in removable air.
G PR. (Mg / m 3) is the concentration of harmful components in the supply air.

The ventilation system should provide a room with a sufficient amount of fresh air. Its design and installation at manufacturing enterprises are regulated by the SNiP provisions. With the calculation of the power of the fan, the length and diameter of the air ducts, the natural and forced inflow of air, as well as other parameters to arrange the ventilation of large industrial enterprises, should be engaged exclusively by specialists. This particularly concerns the production of harmful components and explosive substances.

You can design and install the correctly any ventilation system, if you go to the case competently, observing all the requirements established by the regulatory documentation.

If in the room is stuffy, a fungus was formed in the bathroom on the walls or other unpleasant phenomena is observed, it means that you need urgently. The causes of such problems can be different. For example, the absence of microcracks after hermetic installation of plastic window structures completely prevents the natural ventilation of the premises. In this case, you need to take care of the arrangement of forced ventilation with the fan.

Another reason for the weak intake of fresh flow and poor removal of contaminated air saturated with carbon dioxide, different smells or moisture is the clogging of the air ducts. This leads to the formation of a fungus, which adversely affects human health and is able to cause serious diseases.

But there are cases where the ventilation system works flawlessly, and the problem with a lack of clean air remains. These may be the consequences of the inaccurate calculations of the system, improper installation.

The redevelopment of the rooms, an extension of additional rooms to a private house, which is installed in the air exchange, the installation of sealed plastic windows and other interventions in the building design. When planning the reconstruction of premises, a whole building, it is necessary to re-make the calculation and selection of ventilation.

The easiest way to detect problems with air exchange is a traction check. It is enough to simply bring thin paper or a burning match to the exhaust effect (it is not recommended to apply the second option in rooms with gas installations). If a piece of paper or the flame bend down in the direction of the drawing, it means everything is in order with the burden. If not, there are problems with the removal of polluted air. The main reasons are the air ducts clogged or were damaged during repair.

But there is an output from any situation. You can clean the air channels, if necessary, add additional ventilation elements, pre-making calculations according to the established standards.

Ventilation of any room is a necessary condition, even if it is a warehouse not visited by people. And in public and residential buildings, the ventilation system must be carefully calculated and arranged with regard to standards. For each closed room, including the attic, it is necessary to take into account the system of air exchange, which contributes to the comfortable finding of people. In any residential building, you can see the ventilation holes that are responsible for the flow of fresh air. In public premises, where people are assumed, the supply and exhaust ventilation that carries the circulation of air masses should be arranged. Sanitary standards strictly regulate the device of ventilation systems, taking into account the volume of rooms and the intended number of people in it. Below will look at the types of ventilation systems and the methodology for calculating air exchange.

Validation of ventilation systems

Ventilation systems differ in the degree of complexity of their design. There are several types:

Simple, natural, carrying out the influx of clean air through the channels made in the walls of the building.
Supply-exhaust, having separate channels for admission and for air outflow.
Supply-exhaust, forced, functioning on duct-built channel fans.
Combined or complex, controlling and providing the inflow and exhaust air, as well as regulating temperature and humidity indoors.

The comfort of finding people inside the building depends on the quality of the operation of the ventilation system. Standards for the amount of incoming air are developed and published by Rospotrebnadzor, which monitors the operation of ventilation in public buildings.

General painting of ventilation of modern houses

What you need to know about airflows

The main stages of settlements

Natural ventilation in residential and public buildings is arranged during their construction and does not require additional calculations. Therefore, the conversation will go about forced systems. The priority for the accurate calculations of the ventilation systems is to record the microclimate of the premises. These are permissible and regulatory and recommended values \u200b\u200bof humidity, temperature and air circulation volumes. Depending on the types of the selected system, the tasks are determined - only air exchange or integrated air conditioning.

The calculation of the airflow received from outside is the first and most important parameter adjustable by sanitary and hygienic standards. It is built on the minimum amount of consumption and air expenditures due to the minimum channels and the operation of technological equipment. Definition of air exchange, which is measured by cubic meters of replaceable air per hour depends on the volume of room and its purpose. For apartments, the outdoor air supply is carried out in the room, where, as a rule, residents are for a long time. It is a living room and a bedroom, less often a cabinet and halls. In the corridors, kitchens and bathrooms of the tributary, usually do not, only exhaust holes are installed in them. Air masses come naturally from neighboring rooms where the influx is made. Such a scheme causes airflow to move through residential rooms in the technical, "squeezing" spent air-gas mixture into exhaust channels. At the same time, unpleasant odors are removed, without turning around the apartment or house.

Calculations include two air exchange values:

By productivity - based on air mass standards per person.
By multiplicity - how many times the air change in the room in one hour is occurring.

Important! To select the performance of the planned ventilation system, the largest of the values \u200b\u200bobtained .

Air performance

For residential premises, the amount of air arrived must be calculated in accordance with the construction norms and rules (SNiP) No. 41-01-2003. Here is the number of consumption by one person - 60 cubic meters per hour. This volume should be compensated by the influx of external air. For bedrooms, fewer volume is allowed - 30 cubic meters per hour per person. When calculating, only permanent people should be considered, i.e. You should not take the number of guests attending the room from time to time. For comfortable parties, there are systems regulating air flow in different rooms. Such equipment will allow you to increase the air flow into the living room, by reducing it in the bedroom.

Calculations are carried out according to the formula: L \u003d n x ln, where: L - the calculated volume of the incoming air cubic meters per hour; N is an estimated number of people; LN is a regulatory air flow 1 person. - For bedrooms - 30 cubic meters per hour and for other rooms - 60 cubic meters per hour.

Performance by multiplicity

The calculation of the multiplicity of air exchange in the premises should be carried out based on the parameters of the room, this will require a plan of a house or apartment. The plan should contain the purpose of the room and its dimensions (height, area or length and width). For a comfortable sensation, a minimum is required to complete the entire volume of air.

It should be noted that the supply channels, as a rule, give the volume of air for two-time metabolism, while the exhaust is designed for one-time air exchange. There is no contradictions in this, since the air flow occurs also naturally - through slots, windows and doors. After calculating air exchange for each room we add values \u200b\u200bto calculate the performance of the ventsy system. After that, it will be possible to correctly select the power of the supply and exhaust fans. Regulatory performance indicators for different premises are as follows:

ventilation systems of residential premises - 150-500 cubic meters per hour;
in private houses and cottages - 550-2000 cubic meters per hour;
in office premises - 1100-10000 cubic meters per hour.

The calculation is carried out according to the formula: L \u003d nxsxh, where: L is the calculated volume of the incoming air cubic meters per hour; N - the standard of multiplicity of air exchange: houses and apartments - 1-2, office space - 2-3; S - area, sq.m; N - height, m;

Example of calculating the aerodynamic calculation of ventilation

In the calculations, you can also help this calculator