The installation of effective ventilation is a prerequisite in housing construction, the construction of office and industrial buildings.
It helps create normal air exchange in the room, maintain optimal temperature, ensure air circulation and humidity.
Any ventilation system consists of a set of specific devices and a network of air ducts mounted from plastic or metal pipes of various sections.
The most popular pipe products are made from polyvinyl chloride (PVC), a unique material with improved technical characteristics and performance properties.
Areas of application
Square pipes are used in a number of applications:
- Furniture manufacturing . Fences made from square pipes also look very original, surpassing metal products in certain characteristics.
- Construction works . This applies to both indoor and outdoor use. In agriculture, plastic profile pipes are often used to connect nipple systems that provide duck, goose, rabbit and other drinkers. When selecting dimensions, take into account the thickness of the profile in order to achieve vertical retention of the entire system. When installing, it is important to maintain perpendicularity to the nipple, which will allow you to set up the drip mode without losing water.
- Making greenhouses . The structures are durable and inexpensive.
- Cable channels, air ducts . In this case, a large plastic square pipe is used.
- Production of plastic windows.
Installation and installation in a cabinet
To assemble the air duct, it is enough to have even an ordinary hacksaw on hand. The systems are insulated using sealant. You can buy elements to connect individual fragments, if required. Ventilation can include both plastic and metal pipes at the same time. The latter are in most cases placed at the outlet, and from them branches are made to plastic products. A fan can be used to speed up the air flow in the pipes. It must be taken into account that a large number of bends impairs traction. Ventilation power is reduced by 10% when turning.
In some cases, it is possible to install it in a cabinet when installing an air duct and hood. To do this, you need to install a check valve in front of the ventilation shaft. Next, the algorithm of actions is as follows:
- Make a hole for the air ducts using a jigsaw in the shelves and walls of the cabinet.
- Place a pipe into the resulting hole and secure the joints with sealant.
- Hang the cabinet on the wall, connect the air duct to the ventilation shaft, and secure it with self-tapping screws.
Strengths and weaknesses of square plastic pipes
The strengths of this product include the following characteristics:
- They tolerate climatic influences well.
- Undemanding in maintenance.
- They are not afraid of corrosion.
- Long-term operation.
- Environmentally friendly.
- Water transportation is not accompanied by characteristic noise.
- Excellent hermetic performance.
- Cheaper transportation and storage: this is facilitated by a more convenient form for storage.
List of disadvantages:
- Weak fire resistance.
- Recommendations for limiting contact with heated air.
- Not an easy installation, requiring specific skills and equipment.
- Some products are not suitable for hot water.
Design features
Size
When choosing a suitable plastic pipe, you mainly pay attention to its diameter and cross-section. The walls are characterized by a certain thickness; moreover, in some models one of them may be somewhat thicker. For this reason, it will be necessary to select a section of external and internal type. It is the internal section that requires special consideration during project development. Each section is characterized by its own wall thickness, and these indicators may vary depending on the manufacturer. For example, a 20x20 pipe is characterized by a thickness of 1.5 mm, 35x35 - 3 mm, 50x50 - 4 mm.
Colors
The range of colors is characterized by a certain breadth: these include ordinary white, black, gray colors, and somewhat non-standard green, red, yellow, blue. There are also imitations of various wood species.
Length
Standard sizes for the length of these pipes are 1, 3, 4 and 5 meters. At sales points they can cut off any required piece of 3.5 or 1.5 meters. To connect two separate sections, it is better to use a fitting, and to close the hole, a plug, which must be of a suitable diameter.
How are they produced?
Plastic bends are made on automated production lines. They include loading equipment, a system of devices for melting the polymer mass, forming a workpiece of a certain configuration from it, its further cooling and calibration.
Manufacturing technology
The production of polymer pipe products is based on the extrusion method.
Molten raw materials from polymer materials and additives are forced through the slot of the extruder molding device. The workpiece then goes through a calibration and cooling process. Next, the products are labeled, cut into measured pieces and stacked.
To create multilayer profiles, coextrusion technologies are used, when a new layer of a different polymer composition is applied to each created layer of the product.
A new modification - a fiberglass bend - is produced by pultrusion. The fiberglass blank is passed through a container of polyester resin and then pressed while hot through a molding head.
Installation
A square plastic profile pipe is connected by welding: most often structures and furniture are made this way. It is more convenient to use fittings for these purposes: this applies not only to connecting square products to each other, but also to those cases when a square pipe needs to be joined to a round one. When choosing a connection method, the conditions in which the product will be used are usually taken into account.
Plastic profile pipes of square and round type are connected with rubber couplings: fixation in this case is carried out with clamps. To design the ends of the profile, plug couplings are also available for sale. Adapters are used to assemble pipes with different sections. To connect three square pipes at once, there are tees, where each side is equipped with a clamp.
To improve the result, you should try to reduce the number of joints to a minimum: it follows that unnecessary cutting of the profile should be avoided. If a pipeline made of polypropylene products is being installed, it is important to take into account the coefficient of thermal expansion: if the pipe is heated to + 60 degrees, it lengthens by 9 mm.
If such expansion encounters a lack of space, it may result in a pipe rupture. When installing a volumetric heating system or a pipeline for transporting hot water, it is important to take this factor into account in order to avoid emergency situations. To make the operation of such a system safer, it is equipped with temperature compensators. When laying such pipelines inside a home at a distance of more than 1 meter, close spaces should be avoided. An aluminum layer is included in the composition of individual polypropylene pipes: this makes it possible to reduce the expansion coefficient during heating. For such products a higher price is set.
Advantages and disadvantages of plastic air ducts
Plastic equipment for ventilation, compared to metal counterparts, produces much less noise. The fewer joints there are in the design, the better. Plastic ventilation structures are lightweight, which allows them to be easily transported to the desired location and installed independently. During installation, the pipes must be treated with an antistatic solution so that dust contained in the air is not attracted to the material.
Cleaning plastic exhaust systems is a time-consuming and expensive procedure, so initial treatment with an antistatic agent reduces the need for this process. In addition, this approach allows you to keep the inner surface of the pipes as smooth as possible, which virtually eliminates friction losses. Plastic is used in a wide temperature range from -40 to +90 degrees Celsius, which allows it to be used to remove hot air currents.
Like any other product, plastic ventilation pipes have their drawbacks. These include the rather labor-intensive installation process in cottages equipped with steam protection and a low fire resistance rating. If the system was assembled correctly and with high quality, plastic ventilation pipes will work for a long time and ensure ideal operation of the ventilation system.
Cautions
Possible problems may be caused by installation errors, mechanical damage during operation, or manufacturing defects.
If such damage is detected on a plastic pipeline, you can use one of the following methods to temporarily eliminate the accident:
- Metal clamp . The first step is to stop the movement of liquid inside the pipe, then use a clamp to cover the leaking area by tightening the side bolts.
- Rubber . In this case, the problem area is tied with a piece of rubber: a clamp is installed on top of it or a wire is wound.
- Painting . If we are talking about a minor leak, you can apply paint by spreading it over the fabric winding.
- Glue . The damaged area is cleaned, degreased and degreased. To seal a through hole, it is better to use two-component epoxy glue. In this case, a fiberglass bandage or sealing tape is used to wrap the problem area.
- Cold welding . This way you can connect or repair any plastic pipes. After preparing the surface, the problem area is sealed with plastic material, which is previously kneaded in the hands. Having wrapped the sealed area with a tourniquet, you need to wait an hour, after which the protruding parts of the hardened material are cut off or sawed off.
Selecting the type of duct equipment
Moving on to the problem of choosing an air duct, it is initially worth determining its main purpose, ventilation dimensions and type. For a specific hood, the air duct system is selected individually in order to ensure the highest possible quality of operation of the entire structure. As with all other types of installation work, the installation of a ventilation system should begin with a draft design, in which it is necessary to take into account all issues of the location, installation and operation of the equipment, taking into account the area and other features of the room.
This suggests that it is advisable to entrust the design and installation of a ventilation system to professional companies that have specialists on staff with the necessary tools and level of knowledge. When drawing up a project, it is necessary to correctly calculate the performance of all parts so that the operation of the equipment does not create unnecessary noise and does not interfere with the normal functioning of people.
Many buildings are initially designed in such a way that there is practically no space left for pipelines and the owner of the premises must install ventilation with a narrow cross-section. This means that air in small diameter pipes can produce high levels of noise when the equipment is operating.
The optimal diameter of a plastic ventilation pipe, through which air will move at a speed of less than 3 meters per second, can be calculated using the easy formula: S = 0.9L.
Here, S is the cross-sectional area of the pipe in square centimeters, L is the air flow rate.
Using this formula, you can easily determine the most suitable pipe diameter in this case, which will guarantee a high level of performance of the entire exhaust system. When choosing a team of installers who will install the ventilation system, you should not try to save money on workers offering cheap services, because even a minor error during work or incorrect calculations can lead to a number of troubles in the future.
For example, an air leak from a ventilation system may come from a place with poor sealing, which is quite difficult to find. Ignoring the characteristics of the equipment and premises during installation, as a rule, leads to premature failure of the main hood devices, the repair or replacement of which is quite expensive. The customer has every right to constantly monitor the installation process, make amendments and wishes, and insist on careful compliance with all technological documentation.
Plastic ventilation pipes have their own established dimensions, so replacing a failed part is not much of a problem. You need to know that rectangular and square ventilation structures resist air flow more than their counterparts of other shapes, which makes it difficult for the substance to escape through the system. In addition, profile plastic pipes are more susceptible to noise during system operation. Manufacturers of products with an oval or round cross-section assure potential buyers that installing two round air ducts without corners is much more practical than one rectangular or square one.
However, it is worth noting that such ventilation will have better performance only in a situation where the pipeline runs in a straight line. The cost of tees, turns and other fittings for changing the direction of the structure is twice as high, so in systems with numerous joints and turns, the use of round or oval pipes is unlikely to be convenient and economical.
To prevent unnecessary noise from occurring in rectangular air ducts during installation, you need to lay a layer of soundproofing material that effectively absorbs the sounds emitted by the air during equipment operation and prevents them from entering the room.
