Design and installation of ventilation ducts

 Design and installation of ventilation ducts

Air ducts are designed to move air flow through ducts made of different materials. Designs can be of various purposes, depending on the place of use. The efficiency of ducts is provided by the diameter of the ducts, their shape and degree of rigidity. Often they are performed with rigid or flexible materials, which allows you to create a communication that is optimally suitable for use in certain conditions.

Variety and choice of duct

According to the material

Any air duct can be made of various materials.

  • Flexible hoses. The basis of this material is wire, which is covered with a protective insulating material. The cross section of products is usually round. Also in some models there may be additional sound-absorbing or heat-insulating materials. Usually such communications are used in apartments or wooden houses.
  • Galvanized metal box. Boxes are made on special devices and may have a rectangular or round shape. Also, the sections are different. The peculiarity of the products is that they are resistant to external mechanical influences and can pass through a large amount of air through themselves. Boxes are used for the construction of ventilation in offices, shopping centers and other buildings. In apartments such products are impractical to use.
  • Steel construction. Pipes of boxes are made of thick-walled steel and connected to each other by welding. Products are usually used in industrial facilities for smoke removal.

As can be seen from the above, the best option for the construction of ventilation systems in residential premises will be flexible hoses.

According to the shape of the section

These products differ in the diameter of the air ducts and can be round or rectangular. If there are certain restrictions on the object where the system is being laid, then elliptical sections of ducts can be used. It is also worth considering that with repeated changes in the form of communication, the properties of materials may deteriorate. It is important to properly connect the elements of the system using seals and flanges to prevent air leakage.

By diameter

This value is calculated in each case, the optimal diameter of communications is selected, depending on the volume of the room. There are special tables of SNiPs with which you can choose the best duct. It should be noted that in different types of structures, the air outlet and inflow may not always be the same, and therefore these indicators must be taken into account. The diameter is chosen depending on the material used to manufacture the pipes, the climatic zone of their use, the shape of the pipes, the presence of bends and turns, and the gratings.

Selection of elements in the network and their resistance

Ventilation is a complex engineering system, which can be affected by various factors. Among them note such:

  • system performance can reduce many turns;
  • the length of the duct in an ordinary apartment should be done no more than 3 m, since each extra meter reduces the design efficiency;
  • it is worth avoiding creating elements at right angles when cornering;
  • check valves are recommended;
  • a place of an exit of boxes warming up outside.


A number of chemical and sanitary requirements are imposed on the construction of these systems, and all the installation norms for the box are set forth in documents SNiP 3.05 01 85, CPD, BCH 237-80.


By the number of people

In an apartment building during the construction of a ventilation system, it is necessary to calculate the correct parameters and take into account the number of people who live there. You can do this in a private version or order such calculations in specialized firms. During the event, one should take into account the general network layout, area of ​​the premises, their purpose and number of residents. It is also important to consider the amount of air exchange. It is measured in cubic meters. After this, it is necessary to calculate the air velocity, which should be 1 m / s.

By area

Based on the above parameters, the experts calculate them using charting, which makes it possible to identify the optimal cross-section of the highway for various structures depending on their area. For example, an air duct with a round section of a box with a diameter of 150 mm or rectangular - 200 mm would be optimal for a ventilation system in an industrial room with a volume of 300 square meters.

By the rate of air exchange

When laying and constructing an air duct, it is also necessary to take into account the multiplicity of air exchange and isolate communications, which will help prevent condensation in the network and will become an important component for the smooth operation of the main line. Sometimes it may be necessary to additionally insulate the air duct to ensure the supply of sufficient air to the structure. For the system to function continuously and smoothly, it is necessary to periodically clean the channels. Often this is done without dismantling communications.

Basic rules and steps

Installation of ventilation duct and ventilation ducts must be made correctly. To do this, you must follow certain rules and connect all the elements in series. Experts highlight the following important points:

  • sleeves should be stretched as much as possible in order to avoid their sagging and to improve the air flow head;
  • bends are made of small diameter in order not to lose pressure in communications;
  • in some cases, it will be necessary to connect the earth to the network when organic solid components move along it;
  • Adapters must be installed in the places where communications pass through the walls so that the communications are not damaged;
  • the distance between fasteners should be 40 cm, which will avoid sagging communications.

Installation Features

If required, insulation should be placed on the box. Such components can be purchased separately in the store. Installation is performed using special hardware. All communications can additionally be warmed with mounting foam, and the connection of elements can be done by hand. Hoods must be installed in accordance with the above rules, it is also important to properly organize the device channels, and not just their fastening.

A special feature of the installation is the fact that it is recommended to use ventilation grilles in different rooms where communication systems pass.In one room there should be at least one lattice, which is connected to the sleeves through special conductors and makes it possible to provide access to internal communication. Depending on the duct system, various fastening elements can be used. To avoid additional expenses, it is recommended to use the help of experts for making calculations.

In some cases, the installation uses a nipple or coupling. They can be mounted outside the communications. The flange connection is carried out with the help of spring mechanisms, which allows the system to be made more flexible and prevent it from being damaged by external factors. Not so often used fasteners with bandage. Although this method is distinguished by high tightness, it is rather expensive.

In order to reduce the noise when the line is in operation, it is recommended to use fewer turns throughout the entire communication length. It is also worth avoiding the use of pipes of different diameter. If part of the communications will take place through the air or in open space, it is necessary to produce insulation.In industry, this is done with a special foam that will help not only protect against frost, but also reduce noise. Sometimes you can use foam or special glue to attach foil tape.

As mentioned above, the efficiency of ventilation depends on the regular cleaning of the box. In some cases, it may be necessary to dismantle the system, but often carry out procedures without such measures. Cleaning methods are chemical and mechanical, and they are selected depending on the type of communications and the type of dirt.

The mechanical cleaning method involves the use of aerosols, which allows you to remove plaque inside the boxes. Sometimes the cleaning is done with the help of chemical granules, when dissolved, the active substances come into contact with the contaminants and remove them. It is important to remember that when using chemical methods it is necessary to ensure complete insulation of the pipeline.

Mechanical cleaning involves the use of mechanical devices and pumps that connect to the outlet of the system. In the course of such work, the brushes at the ends of the air ducts clean the inside of the ducts from all types of dirt that the pump collects.Mechanical cleaning is the most favorable and safe if pollution is small.

Sometimes it may be necessary to disinfect the system. This allows you to remove from the communications of bacteria, mites and other microbes. Hydrogen based liquids, powders or aerosols are also used here. It is necessary to disinfect all ventilation systems, as well as take into account the characteristics of the room where they pass. In some places, the use of disinfection is contraindicated and prohibited. These can be schools or kindergartens.

As a rule, when constructing ventilation systems, all these aspects are taken into account, and the possibility of carrying out a full set of measures for cleaning and diagnostics is initially assumed. If you create the system correctly initially, you can organize and select the optimal ventilation line in accordance with the method of its installation, as well as the place of installation. All this will ensure a long and uninterrupted use of communications, regardless of the complexity of the design and the material used.

How to clean the ventilation ducts, see the following video.

Information provided for reference purposes.For construction issues, always consult a specialist.

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