# Ventilation calculation: Principles and Examples for the calculation of the premises

I dream that the house was a healthy climate and is in the same room did not smell musty and damp? To house it was really comfortable, even at the design stage is necessary to conduct a competent ventilation calculations.

If during the construction of the house to miss this important point in the future we will have to solve a variety of problems, from mold removal in the bathroom until the new repair and installation of air duct systems. Agree, not very nice to see the kitchen on the windowsill or in the corners of a child's room hotbeds of black mold, and re-immersed in the repair work.

In the present article we have collected useful materials for the calculation of ventilation systems, reference tables. The formulas, illustrations and real example for different rooms and a certain area, demonstrated in the video.

The content of the article:

• Causes of problems with ventilation
• How to calculate the airflow?
• Sample calculations air volume
• How to choose a section of the duct?
• Conclusions and useful videos on the topic

## Causes of problems with ventilation

With the right calculations and correct installation of ventilation at home is carried out in a suitable mode. This means that the air in a residential area is fresh, with normal humidity and no unpleasant odors.

If, however, the opposite is true, for example, a constant stuffiness, mold fungus in the bathroom or other negative phenomena, it is necessary to check the status of the ventilation system.

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Calculation and design of the ventilation is carried out at the design stage of construction or redevelopment. System is needed to ensure proper indoor climate

During the design and execution of calculations of the ventilation system to select the optimum cross-section of the duct and power equipment

In ventilation systems with mechanical air motivation for his movement meet fans. The supply air fan delivers air into the room, in the exhaust - take him

If ventilation system constructed in parallel conditioning system or air heating, the amount of air supplied has to be taken into account in the calculation

Kitchen hood can not be connected to the ventilation duct. These are separate systems, each of which solves its own problems

Since operating conditions differ in different premises purpose, the calculations are made for them separately

Ventilation system developed not only space, but also for individual building designs. For example, the ventilation of the roof space to arrange the condensate drain from the roofing

Compulsory ventilation system equipped with basements and plinth. Ventilation extend the life of the recessed and ground contact structures, as a consequence, increase the terms of construction operation

Ventilation of a private house in the loft

Ventkanal in the ceiling frame house

The components of supply and exhaust system

Ventilation paired with conditioning

Ventilation grille and output extraction

The exhaust fan in the bathroom

Ventilation of roof space

Intake pipe for the basement

It brings a lot of problems specific to the lack of windows and doors of the finest gaps, triggered by the installation of sealed plastic structures. In this case, the house receives too little fresh air, you need to take care of its tributaries.

Blockages and depressurization duct can cause serious problems with the removal of the exhaust air, which is saturated with odors and excess water vapors.

As a result, in the offices of the colony may appear fungus that is bad for health and can cause a number of serious diseases.

Misted windows, mold and fungus in the bathroom, stuffiness - all clear signs that the premises are ventilated properly

But it also happens that the elements ventilation system It works fine, but the problems described above remain. Perhaps the ventilation system calculations for a particular house or apartment have been carried out properly.

Adversely may affect premises venting their alteration, remodeling, additions appearance, installation of plastic windows already mentioned earlier and etc. When such material changes are not put again to make calculations and to modernize the existing ventilation system in accordance with the new data.

One of the easiest ways to detect problems with ventilation - availabilty thrust. To extract the lattice openings need to bring a lighted match or a sheet of tissue paper. Do not use an open flame when using gas heating equipment in the room for such a test.

Too tight inner doors may prevent the normal circulation of air through the house, reschit problem help special grille or holes

If flames or paper confidently deflected toward the hood, pull there, and if it does not deviation occurs or weak, irregular, a problem with diverting waste air becomes evident. The reason may be clogged or damaged as a result of airway repair tamperproof.

Not always possible to eliminate the malfunction, solution to the problem is often the installation of additional funds exhaust ventilation. Before installing them also does not hurt to make the necessary calculations.

To determine the presence or absence of the normal thrust in exhaust ventilation system at home by using a flame or a sheet of tissue paper

## How to calculate the airflow?

All calculations of ventilation systems boil down to in order to determine the volume of air in the room. As such premises can be considered as a separate room, and a set of rooms in a specific house or apartment.

Based on these data, and data from normative documents calculated basic parameters of the ventilation system, such as the number and section of ductwork, fan power, etc.

There are specialized computational methods allowing to calculate not only the renewal of air in the room, but also the removal of heat energy, humidity change, elimination of pollution, etc. Such calculations are usually carried out for industrial buildings, social or any specialized destination.

If there is a need or desire to perform such detailed calculations, it is best to consult an engineer, studying such techniques.

For the independent calculation of the following options are used for living quarters:

• by the multiplicity;
• on health and safety standards;
• area.

All these techniques are relatively simple, understand their essence, even a layman can calculate the basic parameters of its ventilation system. The easiest way to use the calculation area. Shall be based on the following standards: every hour in the house must be supplied with three cubic meters of fresh air per square meter.

The number of people who reside in the house, it does not take into account.

The ventilation system is arranged in residential buildings such a way that air enters through the bedroom and the living room, and removed from the kitchen and bathrooms

sanitary-hygienic norms calculation is also relatively simple. In this case, the calculation does not use the area, and the data on the number of permanent and temporary residents.

Each resident is necessary to provide fresh air at 60 cubic meters per hour. If the room is regularly present time visitors, then for each such person must be added another 20 cubic meters per hour.

Somewhat more complicated is calculated on the ventilation rate. If it is satisfied to consider the appointment of each individual room and regulations on ventilation rate for each of them.

air multiplicity called coefficient reflecting the number of complete replacement of the exhaust air in a room for one hour. Relevant information is contained in a special regulatory table (SNIP 2.08.01-89 * Residential buildings, adj. 4).

From this table, the calculation is performed by the multiplicity of ventilation at home. The corresponding coefficients reflect the number of air changes per unit of time, depending on the destination premises

Calculate the amount of air that must be updated within an hour, it is possible according to the formula:

L = N * V,

Where:

• N - number of air changes per hour, taken from the table;
• V - the volume of the room, cub

The volume of each room is very easy to calculate, it needs to multiply the area of ​​the room at its height. Then, for each space calculated volume of air per hour from the above formula.

An L for each room is added, the resulting value gives an idea of ​​how much it needs fresh air to enter the room per unit of time.

Of course, through the exhaust ducts It must be removed exactly the same amount of the exhaust air. In the same room is not set and the supply air and exhaust ventilation. Typically, air flow through the "clean" room: a bedroom, nursery, living room, study, etc.

Exhaust ventilation in the bathroom or lavatory installed in the top of the wall, built-in fan is in automatic mode

Remove the air from the room service purposes: toilet, bathroom, kitchen, etc. This is reasonable, because the odors, typical of these buildings do not apply for housing and immediately output to the outside, which makes the stay in the house more comfortable.

Therefore, the calculations take only the norm for air or just for ventilation, as reflected in the regulatory table.

If the air does not need to apply to a particular room or removed from, the appropriate box is blank. For some premises shall have the minimum ventilation rate. If the calculated value was lower than the minimum should be used for tabular value calculations.

If problems with ventilation showed already after repairs in the house was carried out, it is possible to install intake and exhaust valves in the wall

Of course, the purpose of which is not shown in the table in the home can find a place. In such cases, use the guidelines adopted for premises, ie 3 cubic meters per square meter room. Simply multiply the area of ​​a room for 3, the value obtained is taken as the normative air exchange.

All values ​​of the ventilation rate L should be rounded upwards, so that they are multiples of five. Now we need to calculate the amount of air exchange L to space through which the air flow. Separately summing the multiplicity L of the ventilation of rooms, which is produced from the exhaust air diversion.

If the calculation result does not meet sanitary requirements, installing supply valve, Or breather exhaust through the wall, Upgraded the existing system or you are cleaning it.

Cool outdoor air may adversely affect the quality of heat in the building, for such situations used ventilation devices with heat recovery

Then you should compare these two indicators. If L on the inflow was higher than L on the hood, it is necessary to increase the rates for the rooms, which used in calculating the minimum value.

## Sample calculations air volume

To perform the calculation for ventilation system by the multiplicity, to start to make a list of all the rooms in the house, save to the area and ceiling height.

For example, in a hypothetical house has the following facilities:

• Bedroom - 27 sq.m .;
• Living room - 38 sq.m .;
• Office - 18 sq.m .;
• Children - 12 sq.m .;
• Kitchen - 20 sq.m .;
• WC - 3 sq.m .;
• Bathroom - 4 sq.m .;
• Corridor - 8 sq.m.

Given that the height of the ceiling in every room is three meters, calculate the appropriate air volume:

• Bedroom - 81 cu m .;
• Living - 114 cu.m .;
• Cabinet - 54 cu.m .;
• Children - 36 cu.m .;
• Kitchen - 60 cu.m .;
• Bathroom - 9 cubic m .;
• Bathroom - 12 cu.m .;
• Hallway - 24 cubic meters

Now, using the table, you need to make room ventilation calculations taking into account the multiplicity of ventilation, increasing each indicator to the value given above, five times:

• Bedroom - 81 m³ * 1 = 85 m³ .;
• Living room - 38 sqm * 3 = 115 cubic m .;
• Cabinet - 54 m³ * 1 = 55 cbm .;
• Children - 36 m³ * 1 = 40 m³ .;
• Kitchen - 60 cubic meters - not less than 90 cubic meters .;
• Bathroom - 9 cbm not less than 50 cubic meters;
• Bathroom - 12 cubic meters not less than 25 cubic meters

Information about the regulations for the corridor in the table are not available, so the data is based on this small room are not included. calculation is made for the living room area with a view of three standard cubic meters. meters per square meter.

A well-designed ventilation system will ensure sufficient air exchange in the living room. When designing necessary to consider the requirements and norms of building codes

Now you need to separately summarize the information on the premises in which the air flow, and separately - the room where installed air intake device.

The volume of air inflow:

• Bedroom - 81 m³ * 1 = 85 m³ / h .;
• Living - 38 sqm * 3 = 115 m³ / h;
• Cabinet - 54 m³ * 1 = 55 m³ / h;
• Children - 36 m³ * 1 = 40 m³ / h;

Total295 m³ \ h.

The volume of air drawn:

• Kitchen - 60 cubic meters - not less than 90 m³ / h;
• Bathroom - 9 cbm - not less than 50 m³ / h;
• Bathroom - 12 cubic meters - not less than 25 m³ / h.

Total165 cbm / h.

Now it is necessary to compare the obtained amount. Obviously, the necessary flow hood to exceed 130 cubic meters / hour (295 cubic meters / hr 165 m³ / h).

To resolve this difference, it is necessary to increase the volume of air by drawing, for example, increasing the performance of the kitchen. In practice, this is carried out, for example, replacement of the duct section on bólshego channels.

Rules for calculating air channel area for replacement or upgrade venting system It listed here. We recommend to get acquainted with useful material.

After edits calculation results are as follows:

The volume of air on the inflow:

• Bedroom - 81 m³ * 1 = 85 m³ / h .;
• Living - 38 sqm * 3 = 115 m³ / h;
• Cabinet - 54 m³ * 1 = 55 m³ / h;
• Children - 36 m³ * 1 = 40 m³ / h;

Total295 m³ \ h.

The volume of air drawn:

• Kitchen - 60 cubic meters - 220 m³ / h;
• Bathroom - 9 cbm - not less than 50 m³ / h;
• Bathroom - 12 cubic meters - not less than 25 m³ / h.

Total295 cbm / h.

Volumes of supply and exhaust are equal, which corresponds to the requirements of the calculations by the multiplicity of ventilation.

Calculation of the ventilation system for the kitchen is also extremely important. Especially if it uses a gas cooking equipment

Calculation of air exchange in accordance with the sanitary standards is much easier to perform. Suppose that in the home, discussed above, two people live permanently, and two are in the room regularly.

The calculation is performed separately for each room in accordance with the norm of 60 cubic meters \ person for permanent residents and 20 cubic meters \ hour for temporary visitors:

• Bedroom - 2 persons * 60 = 120 cu m \ h;
• Cabinet - 1 person * 60 = 60 cubic meters \ h;.
• Living room 2 people * 60 + 2 people * 20 = 160 cu m \ h;
• Children 1 person. * 60 = 60 cubic meters \ hour.

Totalon the inflow - 400 cubic meters \ hour.

For the number of permanent and temporary residents of the house does not exist any strict rules, these figures are determined based on the actual situation and common sense.

Sufficient amount of air flowing in a timely manner in the bathroom and also timely evacuation of waste to prevent the formation and the appearance of stale air moldy fungi

Stretching is calculated according to the standards set forth in the table above, and to increase the total score on the inflow:

• Kitchen - 60 cubic meters - 300 m³ / h;
• Bathroom - 9 cbm - not less than 50 m³ / h;
• Bathroom - 12 cubic meters - not less than 50 m³ / h.

Total extract400 cbm / h.

Increased ventilation for the kitchen and bathroom. Insufficient amount of extract may be divided between all the premises in which the set exhaust ventilation. Or increase the rate for a single room, as was done in the calculation of the multiplicities.

In accordance with the sanitary standards breathability is calculated in a similar way. Suppose the house area is 130 sq.m. Then on the inflow of air exchange should be 130 m * 3 cubic meters \ h = 390 cubic m \ h.

It remains to distribute this amount in the space of the hood, for example, as follows:

• Kitchen - 60 cubic meters - 290 m³ / h;
• Bathroom - 9 cbm - not less than 50 m³ / h;
• Bathroom - 12 cubic meters - not less than 50 m³ / h.

Total extract390 cbm / h.

The balance of air - one of the key indicators for the design of ventilation systems. Further calculations are carried out on the basis of these data.

## How to choose a section of the duct?

venting system is known to be a channel or channel-free. In the first case, you need to choose the right channels section. If a decision to establish the structure with a rectangular cross section, the ratio of its length and width should be closer to 3: 1.

The length and width of the channel-section ducts with a rectangular configuration, should be correlated as a three to one to reduce the amount of noise

standard speed of the air mass on the main air ducts should be about five meters per hour, and on the branches - up to three meters per hour. This will provide the system with a minimal amount of noise. Air velocity depends on the duct cross-sectional area.

To find the size of the structure, you can use special calculation tables. In such a table to choose the amount of air left, for example, 400 cubic m \ h, and top speed you select - five meters per hour.

Then you find the intersection of the horizontal line of the vertical line with air exchange for speed.

Using this diagram calculating section ducts for ventilation duct systems. Speed ​​of movement in the main duct must not exceed 5 km / h

From this intersection is performed down line to the curve at which to determine the appropriate section. For a rectangular duct it is the value of the area, and to round - the diameter in millimeters. First, do the calculations for the main duct, and then - for the branches.

Thus calculations do if the house is planned only one exhaust duct. If it is supposed to establish several exhaust ducts, the total volume of air drawn must be divided by the number of channels, and then carry out the calculations of the stated principles.

This table allows the duct section to pick up the ventilation channel with the volume and speed of air movement

In addition, there are specialized accrued program, with which you can perform these calculations. For apartments and houses, such programs might even be more convenient, because they provide a more accurate result.

At normal air exchange affects the phenomenon of back draft, With the specifics of where and how to deal with it will introduce the recommended article us.

## Conclusions and useful videos on the topic

Clip # 1. Useful information on the principles of ventilation system operation contained in this video:

Clip # 2. Together with the exhaust air leaves the housing and heat. There clearly demonstrated calculations of heat losses associated with the operation of the ventilation system:

The correct calculation of ventilation - the basis of its successful operation and the guarantee of a favorable microclimate in the house or apartment. Knowledge of the basic parameters on which to base such calculations, will not only design the right ventilation system during construction, but also to modify its state, if circumstances change.

Want to share your own experiences in the calculation and construction of ventilation? Any questions during the familiarization with the information? Found flaws in the text? Please write comments in the block, located below the text of the article.

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