Recently, a galvanized ventilation pipe has become quite common, which has high ductility and is characterized by anti-corrosion properties. Such products can be used in a variety of conditions, but it is important to choose them correctly. As a coating, they use aluminum zinc, consisting of 5% aluminum and 95% zinc.
Flexible ducts have many varieties, but are manufactured according to state standards 14918-80 and are characterized by a high degree of chemical resistance. On sale you can find pipes for ventilation systems, which are characterized by ultra-high resistance to corrosion, as well as temperature extremes, in this case, GOST 5632-72 is used in the production process.
Specifications and GOST
Galvanized ventilation pipe can have a rectangular or circular cross-section, the seam can be seam or welded, and its direction can be straight or spiral. There are various products that can be classified by tightness. But it is possible to operate the duct if the ambient temperature does not rise above 80 ° C. Galvanized ventilation pipe 100 mm - this is the product that starts the range of sizes in diameter. The largest diameter is the limit of 1250 mm. The thickness of the sheet used can vary from 0.5 to 1.25 mm, while the minimum length of the product itself can be 3 m, but the maximum length reaches 25 meters. These products comply with sanitary standards and rules 2.04.05-91; 05/05/01-85.
Galvanized ventilation pipe can be used to transport air with a humidity of 60% or less, and the temperature should not rise above 80 ° C. If the product will be operated under such conditions, then in the production process a sheet of steel is used, which is made by the method of cold rolling. Its thickness should be equal to the limit od 0.5 to 1 mm, while the material must comply with state standards 14918-80. To move hotter air whose temperature will reach 500 ° C, special products that are suitable for transporting gas should be used.
Thickness according to sanitary norms and rules
Galvanized ventilation pipe 100 mm is a product and its diameter, however, this characteristic is not the only one that determines the features of such systems. It is also important to know about the thickness, which is regulated by sanitary standards and rules 11-33-75; 41-01-2003. If the diameter of the duct varies up to 315 mm, then the thickness of the sheet used will be 0.5 mm. If the first parameter varies from 350 to 800 mm, then the product should have walls with a thickness of 0.7 mm; when the diameter increases to 900-1250 mm, the wall thickness will be 0.9 mm. The wall thickness will be 1.2 mm if the diameter is 1400-1600 mm.
Fire resistance
Galvanized ventilation pipe may have a certain fire resistance limit, this characteristic determines how much time the product can last from the start of heating. This parameter is indicated in minutes, it can be found on the duct. For pipes that are used in ventilation systems of high-rise buildings, the fire resistance is 90 minutes, such structures are installed on the ceiling.
If we are talking about corridor walls, then the limit is 30 minutes. Such air ducts belong to the zero class of fire resistance, while today five classes are known. From zero to fifth degree, the fire hazard increases. The pipe can be further protected by a flame retardant. You can do this yourself, but first the consumer needs to clean the outer surfaces of the product.
Duct classification
The described ducts may have a rectangular or circular cross section. Products that were mentioned last are divided into spiral-lock and straight-seam. Pipes with a circular cross section are more advantageous than pipes with a rectangular cross section. Round weights are much smaller, their tightness is higher, and such systems are easier to install.
Rectangular products are interconnected by flanges during installation, but the technology is applied without flanges. The area of use of rectangular pipes are residential houses, offices, schools and industrial facilities. Round ducts are much cheaper than rectangular ducts, their price is 35% lower. The distribution of air in such products occurs evenly, and the sound-absorbing properties are higher.
Features of insulated, spiral-wound and longitudinal-seam products
In thermally insulated pipes, the air temperature does not drop, this eliminates the occurrence of condensation on the walls, which could damage the material. Galvanized pipes work quite noisily, and the presence of an insulating layer performs noise insulation functions. Such a layer can be made of mineral fiber, felt, polyurethane, as well as foam elastomer.
Galvanized ventilation pipe (125) spiral is made of twisted tape, which is obtained by the spiral method, this increases strength and stiffness. In length, such products are usually equal to 3 m. In coiled pipes there are fewer joints, which means that the system has a higher tightness. Straight-seam pipes are cheaper than spiral pipes, because for their manufacture there is no need to prepare a galvanized steel sheet. The length of longitudinal pipes is usually 125 m, as a rule, they are purchased for installation on the street.
Cost of round galvanized steel ducts depending on diameter
Galvanized ventilation pipe 200 mm - this is the most popular product, which will cost 755 rubles. If the diameter increases to 1250 mm, then the price will be equal to 7,500 rubles. a piece. For products with the smallest diameter of 100 mm, you will have to pay 400 rubles. An average indicator with a diameter of 500 mm will cost the consumer 2,800 rubles.