Round air ducts made of galvanized steel: GOST, application

To modern ventilation systems, there are high demands. The quality of its installation depends on the comfort and safety of people inside the building. Therefore, before ventilation is arranged, engineers make an accurate calculation of its parameters.

Round air ducts made of galvanized steel are most often used for similar purposes in industrial and domestic facilities. This is due to their specific characteristics. The more attractive such ducts are, it is necessary to consider in more detail.

Choice of duct

The air duct is an element of the ventilation system, made in the form of a box. It takes a direct part in the circulation of air masses and their exchange with the external environment. This process can occur naturally or compulsorily (with the help of compressors).

The effectiveness of air exchange depends on the type of pipes, their characteristics. Inadequate diameter or inappropriate material will lead to a decrease in the capacity of communications, the appearance of aerodynamic noise.

Round ducts made of galvanized steel are used more often than others. This is due to their features and properties. Important parameters of such products are stiffness, diameter of a section, shape, type of material, and also features of connections of elements of a design.

That ventilating pipes corresponded to modern requirements, them make accordingly to GOST 19904-90.

Characteristics of the material

Air ducts of circular cross-section from galvanized steel, GOST of which presupposes their machine or manual production, today are extremely in demand. They are made from a thin sheet.

Due to the use of such a variety of galvanized steel, it is possible to achieve low aerodynamic resistance. Installation of products is pretty simple. A flange for a round duct of galvanized steel is used less often than a nipple.

From thin-sheeted billet it is possible to carry out air ducts of round and rectangular shape of any section. The life of products from this material reaches 10 years. Galvanizing is not subject to corrosion. It is easy to transport and install on site.

Varieties

Air ducts of circular cross-section from galvanized steel have several varieties depending on certain signs of classification.

By the type of weld, the pipes can be spiral wound or straight. The first are more reliable. Their shape causes additional rigidity and reliability of the duct.

The density and tightness class of the material can be P (dense) and H (normal). In the first case, the products can withstand a pressure of 1.4 kPa. They may be installed in rooms that are characterized by an increased fire or explosion hazard. In conventional buildings, air ducts of class N are used.

Manufacture of spiral-wound pipes

Spiral air ducts made of galvanized steel are made of a strip with a width of 137 mm. It twists in a spiral and is joined by edges like a lock fastener. At the same time, the seam of such a product is always outside.

The diameter of the finished air duct directly depends on the thickness of the galvanized steel billet. For products with a cross section of 150-350 mm, a material of 0.55 mm is required. If the pipe diameter is required 360-800 mm, the thickness of the steel for its production should be 0.7 mm. The widest section of ventilation communications is 850-1250 mm. The galvanized sheet must be 1 mm thick.

Factory production provides for the supply of materials to the pipe length of 3-6 m. If the customer needs to mount the system using a different length of duct, the products are made to order.

Properties of spiral pipes

The popularity of the presented products is explained by their characteristics. In the case of manufacturing a spiral weld, round ducts made of galvanized steel have increased strength. Ribs give the structure rigidity, and a thin sheet of steel ensures the ease of the product.

The tightness class for pipes of the presented variety P. The joints are additionally treated with silicone sealant.

Thanks to the listed qualities, the installation of such products is simple and does not require a large number of connections. For equipping the ventilation system, it is possible to use pipes up to 12 m long.

The air that passes through such communications is additionally twisted. This gives it acceleration and reduces noise.

Straight pipes and their manufacture

The manufacture of a single-seam ventilation system involves fastening the edges of a sheet of steel using a nipple or flange.

For standard dimensions, the sheet is cut automatically. If there is a need to fabricate air ducts from galvanized steel with other parameters, the cut is made manually using special equipment.

After cutting, the workpiece falls on the rollers. They twist the material into a tube of the required diameter. Then the workpiece falls on the folding mill. The longitudinal edge of the duct is machined. Folds are deposited along the entire length.

This method produces short pipes 1.5-2.5 m. For the installation of these products, various shapes are used.

Advantages of straight pipe

If we compare the straight-end round air ducts made of galvanized steel with their rectangular varieties, then the first option is cheaper. They are more "quiet", they have better aerodynamics. They are easier to assemble than rectangular types of air ducts.

But if you compare it with spiral-wound pipes, the straight-legged varieties are more difficult to install. For them it is required to make more connections, since the length of products of this type is rather small.

Therefore, when ventilation is installed in a private house, straight pipe is used. They are cheaper. But in industrial conditions spiral airways are used more often. The fewer connections in the arrangement of the system will be made, the better.

Shaped elements

To make a turn, branch or transition, made of galvanized steel for round ducts produce shaped products. They can be of different diameters and are selected according to the section of the pipe for ventilation.

Elements intended for arrangement and complete installation of the system include such products: tees, turns, umbrellas, tires, transitions, bends, tie-ins and crossings. It happens that when installing ventilation of a complex design, the total amount of shaped products is used in total than the pipes themselves.

Therefore, the quality of their production is no less important than the air ducts. The fewer connections the system has, the better. In the joints over time, dust and debris accumulate. Therefore, the smoother the surface inside, the longer the life of the system will be.

Having become acquainted with such products as round air ducts made of galvanized steel, it can be concluded that this is a rather popular system. Its cost and operational qualities stipulate their relevance for the installation of various ventilation systems. For each type of room you need to choose your own type of pipe.