Square plastic pipes

Pipes with a square section are used in the construction of houses, in industrial pipelines, in ventilation installations. Square products are connected easier than round ones.


Application area

  • Used in the manufacture of furniture. They look original in fences, having an advantage over metal products.
  • Used in indoor and outdoor construction. PVC pipes are used for agriculture: a nipple system is connected to them for drinking bowls for ducks, geese, chickens, rabbits and other domestic animals. Such a pipe helps to keep the entire system upright. Its dimensions are selected relative to the thickness of the profile. Mounting takes place perpendicular to the nipple. This eliminates the loss of water in the drip mode.
  • A greenhouse made of plastic pipes will be durable and inexpensive.
  • Large sizes are used as cable channels, air ducts.
  • Used for the manufacture of plastic windows.

Square pipes are especially in demand in the chemical, oil refining and food industries.

Advantages and disadvantages of square plastic pipes

Advantages and disadvantages


  • weather resistance;
  • undemanding to care;
  • does not give in to corrosion;
  • long time of operation;
  • does not harm the environment;
  • when water is supplied through it, there are no noises;
  • increased tightness.

Transportation of square products will be much cheaper, because due to their shape they can be folded denser than round ones.


  • low fire resistance;
  • contact with hot air is undesirable;
  • complex installation, requiring additional elements and certain skills;
  • Not all models are suitable for hot water.

Types, pros and cons of square plastic pipes



This is the most common type.

Installation is carried out by cold welding or socket method. Rigid profiles are connected by fittings. Laying is carried out in hidden and open form. Polyvinyl chloride is cheaper than galvanized metal materials.

A meter of PVC pipe weighs 5.62 kg. The inner surface is characterized by low roughness, as a result of which the material is self-cleaning and a decrease in liquid pressure is excluded.


  • increased chemical resistance;
  • resistant to chlorine and active substances;
  • resistant to biological organisms;
  • UV radiation does not affect the quality;
  • do not give in to corrosion;
  • environmental Safety.

Disadvantages of PVC:

  • brightens from direct sunlight;
  • sensitivity to shock and bending;
  • do not withstand contact with boiling water;
  • not intended for laying in the ground, require a special box;
  • noise from the flow of water.

PVC square models are widely used in ventilation systems.


The design is represented by single or multilayer rows. The weight of a meter of a polypropylene product is 7.06 kg. The inner surface is smooth. The strength is 28-35 MPa.


  • corrosion resistant;
  • unchanged when exposed to chemical compounds, active substances during chlorination;
  • high degree of biological safety (fungus, bacteria);
  • light weight, easy transportation;
  • some models withstand temperatures from -95° to +140°;


  • low tightness, with the exception of the connection with a node with metal pipes;
  • cannot withstand low temperatures.

Installation is simple, as a sufficient range of fittings is connected to all types of structures. The range of diameters and lengths allows you to minimize the number of cuts during installation.


Used in construction and industry. A profile is made by pultrusion, which is the formation and curing of a rod with impregnated polymer fibers through special high-strength molds (dies).

Fiberglass has a low specific gravity – from 0.4 to 2 grams per cubic centimeter. Ten times stronger than PVC. The dielectric characteristics ensure complete safety. Not subject to corrosion, resistant to aggressive environments, salt, acid and alkali. Also, this material is not afraid of hydrochloric, sulfuric, nitric, acetic, phosphoric acid (depending on concentration), sodium hydroxide, ferric chloride.


  • coefficient of thermal expansion is low;
  • resistant to water and temperature differences (withstand temperatures from -60 degrees to +80 degrees);
  • light material;
  • high fire resistance;
  • pleasant appearance;
  • high thermal conductivity;
  • high resistance to moisture and water;
  • biological stability.

Flaw – low degree of thermal insulation.


Design features


The main characteristics when choosing a plastic pipe are diameter and cross section. The walls have a certain thickness, and in some models one of them is also thickened. Therefore, the external and internal sections are distinguished.

It is the internal section that is taken into account when planning projects. Popular diameters of plastic square pipes in mm:

10×10 20×20 30×30 45×45 80×80
15×15 22×22 35×35 50×50 100×100
16×16 25×25 40×40 60×60 120×120

The wall thickness for each section will be different. Specifications vary from manufacturer to manufacturer. For example, a 20×20 pipe has a thickness of 1.5 mm; 35×35 – 3 mm; 50×50 – 4 mm.


The color range has been expanded: from standard white, black, gray colors to green, blue, red, yellow. There are pipes with imitation for various types of trees.


Pipes are produced in standard sizes of one, three, four and five meters.

It is not difficult for distributors to cut the desired length of 3.5 or 1.5 meters.

Fittings are used to connect two segments, and plugs selected according to the diameter of the section are used to close the holes.



The connection of square plastic pipes is permissible by welding, but this method is more often used for structures or furniture.

The connection of the segments with each other or the profile of a square section with a round one occurs with the help of fittings. When choosing an element, the operating conditions should be taken into account.

Coupling connects a square pipe with a round one, made of rubber, fixed with clamps. The plug sleeve is a rubber element that is installed at the end of the profile.

Adapter connects pipes of different sections, a square with a circle.

Tee unites three square pipes, fixed on each side with clamps.

The fewer joints, the more reliable the result. Therefore, without a reason, you should not cut the profile in order to avoid accidents, leaks, and depressurization.

When equipping a pipeline made of polypropylene, the coefficient of thermal expansion is taken into account. The pipe heats up during normal operation up to 60 degrees, while the length will increase by 9 millimeters.

When the expansion does not have enough space, the pipe bursts when heated. Installation of a volumetric heating and hot water supply system requires this factor to be taken into account, otherwise a pipe rupture will occur.

For the safe operation of the pipeline, temperature compensators are added. The pipeline in the house with a length of more than 1 meter is not recommended to be equipped in a cramped space.

Some polypropylene pipes contain a layer of aluminum foil in their structure. In this case, the expansion coefficient decreases with increasing temperature. The cost of such a product is higher.


Leak and repair

The reasons are violation of installation, mechanical damage during use, defects in production.

Temporary measures include:

metal clamp

To begin with, the heating and water supply are blocked. The clamp is put on the place of leakage, the bolts are tightened on the sides.


Rubber patch. In this way, plumbing and heating are repaired. Wrap a piece of rubber around the problem area, clamp it with a clamp, tighten it. It is permissible to drag with wire or cord.


Small leaks can be fixed with paint. Wrap a piece of fabric on the problem area, dye it. Shut off the water until completely dry.

A reliable solution would be to replace the damaged area.


Having previously cleaned the damage, expand it to the maximum, degrease and dry it. Apply silicone sealant.

The through hole is sealed with a two-component epoxy adhesive. The problem area is prepared as described above, wrapped with a bandage made of dense material, such as fiberglass.

After winding 5 layers, covered with epoxy glue. Instead of a bandage, a sealing tape is used, represented by an impregnated adhesive cloth.

It is glued without folds, the material is applied tightly. The next layer half overlaps the previous one. The tape does not tolerate the sun’s rays, so its surface is covered with a protective layer.

Cold welding

Connection of plastic pipes for all purposes. The surface is treated with sandpaper, degreased. The required amount of material is kneaded in the hands until brown, according to the principle of plasticine.

Next, you need to apply to the problem area, press down with a tourniquet. After an hour, saw off or cut off irregularities, as it will harden. The process is accelerated with a hair dryer.

When performing work, observe safety precautions! Use gloves and goggles.

The functionality of the square shape allows you to implement projects of varying complexity. And an attractive appearance will decorate the design of the room when using a square plastic pipe in any design.

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