A complete overview of ventilation pipes of different types, sizes, properties of innovative materials

Since the mid-60s, a new era in the production of ventilation pipes began: in addition to traditional rectangular products, round ones appeared. Only in the late 70s, scientists became interested in air exchange in the premises, and after 10 years the diameters of the air ducts began to be standardized. Today, the choice of ventilation pipes can satisfy any need. The matter is small: which pipes are better to choose and how to correctly calculate the ventilation parameters.

Requirements for ventilation pipes

Supply and exhaust pipes for ventilation must meet the following requirements:

• tightness;
• the level of aerodynamic hum that does not exceed sanitary standards;
• must ensure the free passage of air masses at a speed set by the project;
• keep the air pressure corresponding to the project;
• comply with thermal insulation standards;
• fit into the interior of the building without taking up extra space.

Trying to find an answer to the question: which pipes are better for ventilation of a residential building or apartment, first, let's pay attention to the cross-sectional shape.

Rectangular and round ventilation pipes

Air ducts can be circular or rectangular. Round and rectangular ventilation pipes are used in supply and exhaust ventilation with forced or natural draft. There are 22 standard cross-sections of round pipes from 100 to 2000 mm. Pipes with outer diameters over 500 mm are classified as large. It is allowed to lay straight sections of highways with a duration of 2.5 to 6 meters.

Pipes of rectangular cross-section are produced with standard cross-sections from 100x150 mm to 1600x2000 mm with a pitch of 50 mm. Straight sections of highways can be no more than 2.5 m in length. To connect the segments to each other, turns and branches, shaped ventilation elements of the corresponding diameters and shapes are produced.

The sectional shape is selected depending on the size and purpose of the room. So, in small rooms with low ceilings, flat rectangular ventilation pipes will be less noticeable. Although, in terms of aerodynamic properties, they are significantly inferior to round ones. This is because corners create resistance, increase noise and reduce air velocity. Therefore, rectangular pipes in the ventilation of residential premises are additionally insulated.

When installing industrial ventilation systems, pipes of circular cross-section with a large flow capacity are often used.

Plastic ventilation pipes

Metal and plastic are the two main competitors in the ventilation pipe market. Which pipes are better for ventilation: metal or plastic? The answer depends on the particular air environment and project requirements.

Plastic rigid and flexible ventilation pipes are made from the following types of polymers:

• PVC or polyvinyl chloride;
• polypropylene;
• PVDF or fluoroplastic;
• polyurethane or polyurethane foam.

Among the owners of small cottages and apartments, the most popular PVC pipes for ventilation, as the most inexpensive, easy to install and easy to use. They are protected from destruction by ultraviolet light and have a sufficient operating temperature range (from 0 to +80 degrees).

Plastic and PVC ventilation pipes have a number of other advantages:

• the design is perfectly sealed;
• aerodynamic hum in the system does not exceed sanitary standards;
• PVC pipes for ventilation are cheaper than polyethylene and metal analogues;
• neat and look good in the interior;
• a wide selection of shapes and sizes of sections allows you to achieve the required parameters of the system;
• many plastic elements allow you to assemble a line of any shape;
• safe for human health, do not emit harmful substances.

Polyethylene pipes for ventilation are manufactured with antistatic protection. Unlike PVC, polyethylene pipes for ventilation can be operated at temperatures from -40 to +80 degrees. Polyethylene pipes for ventilation with UV protection contain black soot, so they can be distinguished by their color.

Polypropylene pipes withstand contact with aggressive media and moisture, temperatures from +1 to 98 degrees Celsius. Non-flammable and antistatic models have been developed for special use. At negative temperatures, the material becomes brittle, therefore it is used only in warm rooms.

The strongest and most resistant to aggressive environment pipes are made from fluoroplastic (PVDF)... They are installed on the supply and exhaust air, they can withstand contact with vapors of most alkalis and acids, temperatures from -40 to +140 degrees. Therefore, such air ducts are installed to transport air masses containing the most aggressive components.

Many advantages make plastic pipes very popular in private home construction. And only weak fire resistance limits the use of PVC pipes in industrial ventilation.

Metal ventilation pipes

Metal and tin pipes for ventilation are made from:

• galvanized black sheet steel with a thickness of 0.5 - 1.2 mm;
• stainless steel AISI 304, 321, 316, 430. Sheet thickness 1 - 5 mm;
• aluminum;
• galvanized steel;
• thin sheet black steel.

Ventilation pipes are rarely made of sheet aluminum; foil is more often used. Pipes for ventilation up to 50 cm in diameter are made of 0.55 mm thick sheet metal. Elements of large diameters are made of sheet steel with a thickness of 0.7 mm.

Pros of rigid metal pipes:

• durable, strong;
• smooth inner tube surface provides good aerodynamics;
• dirt, dust and soot do not accumulate on smooth walls;
• withstand high pressure and temperature;
• due to their high hygienic qualities, they are used in facilities with increased requirements for sanitation;
• withstand the effects of aggressive environments.

Let's compare some characteristics of pipes made of different materials.

Table 1. Operating temperature ranges for ventilation pipes made of different materials

Galvanized. According to GOST standards, galvanized steel pipes are allowed to be used in areas with any climatic conditions for any type of ventilation, except for the transportation of aggressive gas and air mixtures. A zinc layer protects the pipe from corrosion, and even in damaged areas, a protective film is formed when it interacts with oxygen.

Stainless steel. Corrosion-proof pipes for ventilation are suitable for transporting aggressive air mixtures, hot vapors and gases. Pipes can withstand high temperatures and are very durable, therefore stainless steel ventilation is often installed in industries. To ensure fire safety, stainless ventilation pipes are additionally wrapped with mineral wool.

Black steel. Black steel pipes are installed in ventilation, aspiration and smoke removal systems. They are characterized by increased heat and fire resistance, more rigid than galvanized or stainless steel. Thanks to the welded seams, the black steel pipes are hermetically sealed.

Features of black steel air ducts:

• are made from cold-rolled mild or hot-rolled black steel;
• metal thickness 1.5 mm; 1.4 mm; 1.2 mm;
• pipe length from 125 cm to 250 cm;
• flange connection of pipes.

Welded black iron pipes are available in round or rectangular sections. The pipes are primed from the inside and outside.

Manufacturing technology of metal ventilation pipes

When choosing the best pipes for ventilation, the technology of their manufacture can play a certain role. There are two production methods for ventilation pipes made of sheet metal and steel:

Method for the production of longitudinal welded pipes

The pattern of the future pipe is cut on a guillotine machine. It enters the roll forming machine and here the pattern is rolled up lengthwise into a pipe of the required diameter using the cold roll forming method. The edges of the sheet are fastened together by welding or folds. The second method is easier to implement and therefore more common. At the same time, additional material goes to the folded lock, it does not ensure tightness. You can solder or weld sheets with a thickness of 1.5 mm. Such a connection is hermetically sealed, but more laborious.

Roll-forming machines produce rectangular pipes. Round air ducts are cut in the same way, after which they go to three-roll mills for rolling to the required diameter. Pre-rolling machine is set to the required pipe diameter and metal thickness.

Spirally wound pipes production method

Making pipes with the second method takes less time, but requires more material. Strips - a metal tape is curled into a ventilation pipe. Adjustment of the machine for metal thickness and duct diameter is made by replacing standard dies. The production of coiled ventilation pipes eliminates complex fastening work: welding or making a seam. Therefore, the cost of twisted ventilation pipes is lower, and the technical characteristics are not inferior to longitudinal ones.

Flexible pipes for ventilation

Flexible ventilation pipes are made from aluminum foil or reinforced plastic. The aerodynamic properties of flexible ventilation pipes are comparatively weak. Therefore, they are usually used to form turns in difficult areas, including for transporting media with temperatures up to +250 degrees.

Aluminum ventilation pipes are composed of several layers of foil. They bend well, lightweight and easy to carry. Their length in a stretched state increases by 3 times. But the corrugated inner surface reduces the throughput of the ventilation pipe. Plus, dust collects in the folds.

To neutralize the disadvantages, plastic and aluminum flexible ventilation pipes are installed only fully extended.

Polyester corrugated pipes for ventilation made of several layers of plastic and metal foil. The structure is stiffened by a hardened steel wire frame. Plastic flexible air ducts withstand temperatures from -50 to +70 degrees.

One of the main problems with flexible ducts is high pressure losses along the route. They can be calculated using the diagram.

Due to the low throughput capacity, flexible ventilation pipes are suitable for systems with an air speed of no more than 30 meters / sec and low pressure. Therefore, they can be safely recommended as air ducts for kitchen hoods and household exhaust fans.

Insulated air ducts

Heat and sound insulated flexible air ducts do not require additional sheathing of ventilation pipes. Insulated pipes for ventilation are made of plastic, at the same time they differ in increased sound insulation. The inner perforated layer is covered with a special protection against diffusion, followed by a layer of mineral wool, which is protected by several layers of polyester and aluminum foil. The thickness of the insulation of the insulated ventilation pipe is 2.5 cm. Pipes of this series are produced with diameters of 10.2 - 50.6 cm. The insulated pipe can withstand a ventilation temperature of -41 +135 degrees Celsius. The head of the insulated ventilation pipe will not freeze up in winter. Such ventilation pipes are suitable for metal roofs, soft shingles, ceramic tiles or corrugated board.

Sandwich pipes

Sandwich pipes for ventilation and smoke removal are also classified as insulated. They are two metal pipes arranged coaxially. The gap between the pipes is filled with non-combustible insulating material.

Ventilation sandwich pipes for chimneys are often made of high strength stainless steel on welded joints. The outer pipe can also be made of galvanized sheet, but ventilation from stainless sandwiches looks better and lasts much longer. It is only necessary to put a cap on the head of the ventilation pipe and the exit is ready.

Such pipes are suitable for chimneys and external ventilation, which, according to the requirements of technical supervision, must be insulated. Sandwich pipes are connected to each other using a bell-shaped method. The cost of a stainless sandwich pipe is 1 \ 2 higher than a combined one.

Textile ventilation pipes

New in ventilation - technical textile pipes... Such air ducts are installed on the supply side and, due to their special properties, evenly distribute the air throughout the entire volume of the room. More common are textile air ducts of circular, semicircular or quarter-circular cross-section, but it is technically possible to produce rectangular ones as well.

Characteristics of textile air ducts:

• work in the range of -40 +280 degrees;
• resistant to moisture and chemicals;
• antibacterial;
• have a small mass;
• textile ventilation pipes have a high flow capacity;
• easily repaired and cleaned;
• last longer than 10 years;
• can be combined with air ducts and elements made of any materials;
• can be of different colors.

Due to the variety of colors, in many cases, ventilation from textile pipes does not need to be sheathed with boxes. It fits neatly and harmoniously into the interior. Special-purpose pipes have anti-static, anti-corrosion or fire-fighting properties.

Ventilation pipe diameter

Having decided on the material, you can choose which diameter of the ventilation pipes is optimal. Knowing the frequency of air exchange for your room, you can choose which diameter of ventilation pipes is suitable. The air exchange rate is determined according to the SNiP tables, it will come in handy further, and now it is necessary to determine the volume of the room by multiplying its overall dimensions.

Now we calculate the air exchange for a particular room:

O=n*Vto,

here Vк - the volume of the room, n - the rate of air exchange from SNiP.

As a rule, for residential premises, it is sufficient to determine the supply or discharge of air. Industrial ventilation is built on the basis of both indicators. Having received the value of O, it is necessary to increase it in such a way that it is divisible by 5.

The inflow and exhaust values ​​should be a ratio that depends on the purpose of the room. For residential premises, the supply and exhaust are always the same. In production, it is often necessary to create an air pressure in the service area or, on the contrary, to discharge it.

When the total volume of air is obtained, according to the diagram, we choose which pipe diameter for ventilation is optimal. And one more value that is important for the quality operation of the system: the length of the section of the exhaust ventilation pipe above the roof.

The length of the section of the exhaust ventilation pipe depends on the section and is selected according to the table. In the leftmost column is the width, in the grid - the cross-section, in the top line is the height of the head of the ventilation pipe.

• The length of the ventilation pipe must be equal to the length of the flue pipe. Otherwise, you cannot avoid drawing smoke into living rooms;
• Above a flat roof, the height of the pipe must be more than 50 cm.

Calculation using the program

The use of special programs greatly facilitates the calculation of all ventilation parameters. During the calculations, climatic indicators, the shape of the pipes and even the material from which they are made are taken into account. Additional resistance to air flow in ventilation is created by grilles, filters, nets and turns, which are also taken into account in electronic counting.

Video on how to correctly calculate the height of the chimney: