Plastic ducts for ventilation: varieties, recommendations for selection + ventilation duct arrangement rules

Alexey Dedyulin
Checked by a specialist: Alexey Dedyulin
Author: Violetta Ukhinova
Last update: May 2019

Much has been said that all plastic products clog nature. Why it happens? That's because plastic is a very "long-playing" material. It decomposes poorly: products from it are very durable and reliable. Plastic ducts for ventilation will last much longer than the same galvanization. But how to choose them?

You will learn all about the varieties of plastic ducts and how to assemble them from the article we presented. We will tell you in what order the plastic ventilation ducts are laid. We will explain how to assemble individual parts into one perfectly functioning network and how to fix it.

Tips for choosing plastic ducts

Ducts are nothing more than pipes through which air circulates, providing ventilation of the premises. They can be metal, in some cases, for example, in risers, asbestos-cement or plastic.

Now it is plastic that is most popular. With its comparative cheapness, it serves much longer than metal, which is subject to corrosion, or asbestos cement, eaten by dampness, excessive dryness and other external factors.

Round plastic ducts
The photo shows far from a complete variety of solutions for connecting round plastic segments into one high-quality and tight ventilation network. But this diversity is enough to understand that with their help it is possible to assemble ducts of the most varied degree of complexity

What to consider when choosing plastic ducts:

  1. The inside of the plastic pipes should be extremely smooth. In this case, air friction against the walls will not occur at all, and air flows will circulate in such a structure with the greatest efficiency. 
  2. In the case of installation of natural ventilation, not reinforced by fans, it is better to refuse corrugated pipelines. The corrugated walls of the vencanals, especially at bends, will delay the flow of air and ventilation will not be carried out at full strength. 
  3. Preference should be given to the manufacturer whose joints of the plastic duct segments are carried out with the best tightness. 

Too hard plastic is a bad sign. When pressed, the pipe should give in slightly. Excessively dense and coarse material will last less than soft. Most likely, it will begin to crumble and crumble during the first decade of using the ventilation system.

Segments of plastic sewer pipelines
But the remark on hardness does not apply to plastic sewer pipes manufactured using a different technology. Such dampness is not afraid of dampness, nor dryness, nor frost

If the owner decided to mount ventilation system of such pipes, he can be sure that it will serve no less than that which is mounted from pipes specially designed for assembling duct systems.

The only drawback of sewer pipes is their exclusively round volume profile, which is not always convenient.

The main types of ducts

All plastic ducts can be divided into three categories:

  • Round. Demanded for laying routes of ventilation systems. The most common diameters of these are 100, 125 and 150 mm.
  • Rectangular. Involved when you need to install ducts over a suspended ceiling. The most popular sizes are 60x120 and 60x204 mm. Although it is possible to purchase narrower modifications.
  • Flexible. They can be both round and square.

The flexibility of the material is ensured by a spiral reinforced external "frame", which envelops the inner tube of PVC material - vinylurethane.

Quadrangular plastic pipes for ventilation
Just like with round pipes, the connecting solutions for quadrangular plastic pipes look the most diverse way. For a project of any degree of complexity, you can choose a corner or fitting that will fully satisfy the given conditions

Often, along with the above, during the installation of plastic pipelines, sewer polymer pipes are also used.

Technical advantages of plastic

As already mentioned, service life is one of the most important criteria by which people give preference to plastic.

Along with a long service life, air ducts made of this material:

  • They have a lighter weight than the other materials from which the segments of the ventilation system are made.
  • Not afraid of slight sagging - permissible up to 4%.
  • They are easy to install, because they are remarkably cut with a hacksaw for metal or a grinder.
  • In the area of ​​the roof do not require enhanced thermal insulation.
  • Inside they have very smooth walls, which makes air circulation through such pipes more active and easier.

You can often see that the owner mounts ventilation from the most common PVC sewer pipe. They are cheaper, provide excellent sealing, and a wide range of fittings, tees, revisions, etc. gives them the opportunity to mount a ventilation system of any degree of complexity.

Ventilation from sewer plastic pipes
A variety of connecting solutions gives excellent soil to those who decided to install a high-quality and at the same time low-cost ventilation system from round plastic sewer pipes

But whatever the shape of the air ducts, the ventilation system should always fit into the SNiP framework, which states how any ventilation system should be equipped.

Basic rules for arranging a ventilation duct

Next, we will talk about how to properly design a ventilation duct and what to look for when developing a project.

In addition, the recommendations of specialists on arrangement of a ventilation system. And let's start by charting the future ventilation system.

The main requirements of SNiP

Not all today resort to the services of specialists. Many do the design of the ventilation system with their own hands. But with benefits SNiP 2.04.02-84 and 2.04.01-85 Be sure to familiarize yourself.

Ventilation scheme and proper arrangement of headings
The diagram clearly shows how the ventilation system works. It is separately shown how the arrangement of the ends of the outlet ventilation pipes should be carried out. Regardless of the distance from the ridge, it is advisable to make the ends of the natural air circulation ducts above the highest possible roof point

It is in them that the conditions for the correct installation of ventilation systems in private homes are prescribed.

And here is the basic list of requirements:

  1. Without fail, in any private residential building, the inflow and outflow of air masses must be ensured not only in the rooms where people live directly and spend most of the time (bedrooms, living rooms, kitchen), but also in utility rooms, such as a bathtub, toilet, laundry, etc.
  2. Air exchange must be carried out by mounting supply and exhaust channelsas well as slit ventilation.
  3. The circulation of air in the home should be facilitated by the correct arrangement of the doors. The gap between the floor and the lower end of the canvas is at least 20 mm.

It happens that the hood works much stronger than the inflow. The problem is solved by airing the room with open windows. Under these conditions, this clause cannot be neglected.

It is advisable that the supply duct be located near the heat source - the heating system, heating radiator, etc., which will make it possible in the winter to get the air entering the house along the way.

Installation of plastic ducts
In this photo you can see that the owner decided to combine quadrangular pipes with round ones. In fact, the conductivity of air ducts differs little from the cross-sectional profile. But it is generally accepted that in this regard, a round pipe shows itself better

In principle, nothing complicated to develop ventilation schemes no. You can simply take a schematic drawing of the building, and draw on it the wiring of future ducts, focusing on a set of the listed rules and norms.

On the rules for calculations to determine the area of ​​air ducts in detail written here We recommend reading useful information.

Recommendations for arranging ventilation

Let's move on to the assembly of the natural circulation ventilation duct.

The list of recommendations on this subject is as follows:

  1. If you are going to mount a natural ventilation system, then in this case it is better to opt for smooth plastic pipes, rather than corrugated ones. The corrugation is more suitable for the supply and exhaust system, reinforced with axial fans, due to which the air circulation is forced.
  2. In your projects, you should try to avoid a large number of sharp turns of the ventilation pipe. The smoother the bends, the more intense the natural air circulation will be.
  3. The following recommendation follows directly from the previous one. The shorter the air will travel from the “inlet” to the “outlet”, the more efficient ventilation will be.

Therefore, when developing a project, preference should be given to the simplest and most uncomplicated schemes, without cluttering them with convenient for planning, but reducing the efficiency of the system ornate paths.

Mounting the ventilation system under a suspended ceiling
Quadrangular pipes, a great option to save space in the apartment, which will subsequently be equipped with suspended ceilings. The narrow profile of the quadrangular pipe saves 5 to 10 cm in height

When installing a ventilation system from plastic pipes you should definitely pay attention to the most important point - the height of the system itself.

If the chimneys rise above the lowest level by less than 5 meters, natural ventilation will be ineffective. Here, whatever one may say, you will have to strengthen the system with fans.

But for many it can be much easier to build pipes over the roof. In case of low buildings, the enlarged pipes of the air ducts do not always look personal, but in terms of giving aesthetics, you can think of a peculiar camouflage design for them. And in some cases, decisions are the most aesthetic and attractive.

Fan reinforcement

The development and installation of a forced ventilation system also has its own nuances, compliance with which is mandatory. Otherwise, the system will either be underdeveloped, or vice versa.

Exhaust fan
Such fans are inexpensive, last a long time, are easy to install and connect, and without any effort they can strengthen the ventilation system of any complexity and length

According to experts, the main thing that you should definitely pay attention to in the case of a forced ventilation system is:

  1. The difference in the operation of exhaust and exhaust fans. They should be adjusted so that the fan is slightly underdeveloped at the inflow, and processed at the outlet. Thus, a certain air shortage will always be felt in the system, which will contribute to a more effective interchangeability of air in ventilated rooms.
  2. In the case of a forced ventilation system, it does not matter where fresh air is taken from - from above or from the level of lower floors. The main thing is that the rule of the previous paragraph is observed in the system.
  3. The most optimal air exchange for both natural and forced ventilation systems made of plastic is air exchange with a rate of air renewal in the room of 100% in 1 hour. For example, if the room has a total area of ​​40 square meters. meters, the air exchange should be approximately 120 cubic meters of air per hour.

It should also be borne in mind that in the room the exhaust duct must be equipped with at least 25 cm from the ceiling.

Installation of ventilation from plastic pipes
Recently, during construction, plastic ventilation pipes have been preferred not only by private traders, but also by contractors performing large projects

Network Linking

Particular attention is drawn to the fact that it is unacceptable to combine ducts coming from rooms of different directions. If the canal belongs to a utility room, for example, a laundry room, a bathroom, etc., it is by no means recommended to combine it with a canal circulating air in a living room - a bedroom, a living room, and even in the hallway.

These rules are mandatory regardless of which materials ducts will be mounted - whether it is plastic or galvanizing.

In the case of arrangement of some "specific" rooms and heating / heat generating devices, there are requirements. For example:

  1. The kitchen must be equipped own ducthaving no alliance with others.
  2. A fireplace should also have its own chimney, if there is one in the building. In no case should any other ventilation ducts flow into it. You should also pay attention to the fact that it is strictly forbidden to use plastic pipes for a fireplace or stove.
  3. When designing an exhaust system oriented to a stove, it should be borne in mind that it should never be combined with the air ventilation of the kitchen room itself.

If there are several bathrooms in the building, then their plastic ducts are not forbidden to combine together. But at the same time, it is recommended that they be retrofitted with a valve that does not allow polluted air to enter back into the room.

Airflow Combination
This example shows that at least three ducts from neighboring rooms are combined into one.But do not forget that you can combine among themselves the air flows of segments of the housing similar in their orientation

It should be remembered that the streams coming from living rooms should in no case merge with the streams coming from technical rooms.

The output of channels through the roof

It is always advisable to raise the tip of the plastic duct as high as possible. A minimum can be considered a height of 0.5 m above the level of the ridge, if the ventilation pipe exits at a distance of no more than 1.5 m from it.

Otherwise, if the distance of the output part of the plastic air pipeline is more than one and a half meters from the ridge, it is allowed to make the upper tip slightly lower, but it should still rise above the ridge by at least 10% of its outer length.

Roof ventilation outlet
The head should always rise above the ridge by at least 10% of its outer length. Otherwise, the ventilation system may not work. Or, exhaust fans must be at the outlet

To facilitate the work on the device passage through the roof they are desirable to combine through a mine box. It can simultaneously include up to 6 plastic pipes coming from rooms of the same orientation, for example, bedrooms, living rooms, halls, etc.

In this case, the roof will have to equip only one hole for the duct, and not 6, for each pipe. The output of plastic air ducts under the visor is not forbidden, but only if the space under it is well ventilated.

The upper part of the head of the plastic duct is not allowed to be located less than 3.5 m from the nearest windows or balconies. Vent risers must be equipped deflectors: conventional “fungi” or turbine-type devices.

With the rules and formulas for calculating the speed of air mass movement through the duct next article, which is strongly recommended to read.

Conclusions and useful video on the topic

The advantages of arranging a ventilation system of an apartment building with plastic pipes will be discussed in the following video:

The installation of the simplest natural ventilation system made of plastic pipes is shown in the following video:

From the foregoing, it is clear that it will be much easier to install a home ventilation system from plastic pipes and, most importantly, cheaper than from the same galvanization.

And with all the variety of all kinds of connectors, adapters, etc., it will not be harder to do this than to assemble a house from a children's designer.

Want to talk about how you picked up a kit for the device of the duct from plastic and assembled it with your own hands? Do you have information on the topic of the article that will be useful to site visitors? Please write comments, post photos, share information and ask questions in the block below.

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Visitors Comments
  1. Phill

    The option is excellent and practical, but it is more suitable for metal processing workshops. Or for storage facilities where wood, metal, and other materials are stored, because for them any moisture is destructive. The main thing is that there is not a very hard plastic, in which I completely agree with the author of the text. It is also desirable that the exhaust duct be flush, or almost flush, to the ceiling.

  2. Nikita

    I have a ventilation project for my home. Can I replace metal ducts with plastic ones in order to save?

    • Expert
      Alexey Dedyulin

      Hello. Of course, you can replace metal ducts with plastic ones, but this can lead to incorrect operation of the entire ventilation system.

      The fact is that in the calculations, indicators such as the resistance of the material were used, but for plastic and metal it is different. Accordingly, other volumes will pass through the air ducts, which was originally laid down in the project. Therefore, there are two options:

      1. Redo the project for plastic ducts;
      2. Leave it as it is.

      The first paragraph is advisable if you perform the calculations for free.