Diameters of polyethylene pipes: external, internal, purpose of pipes

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Today, polyethylene pipes are widely used in the repair and construction of pipelines, in automatic irrigation systems, in the construction of swimming pools and the construction of artesian wells. In the latter case, we are talking about the transportation of groundwater.

However, before buying such products, it is important to familiarize yourself with some parameters, among them the purpose, inner and outer diameters, as well as characteristics and operating conditions. In polyethylene, like in any other material, the scope is due to physical properties. Today, low, high and medium pressure polyethylene is known, which depends on the production method.

Applications

High density polyethylene has the lowest mechanical strengthpressure. It is used in the production of sewer pipes and as a protective sheath for cable lines. The low pressure material is very durable. It is also called high density materials. It goes to the manufacture of pipes for pressure pipelines. They are able to withstand high mechanical loads and pressures. The limitation of all types of polyethylene is fusibility. At 80 ˚С, the material begins to soften, and melts already at 105 ˚С. This property is decisive when using such pipes.

Scope of application is limited to high temperatures. But the described pipes are used in different areas, namely:

• when arranging sewerage;
• when digging wells;
• when laying cold water supply;
• when arranging irrigation systems;
• when laying gas supply systems;
• in electrical work.

What is the limited application

Polyethylene products are deformed when exposed to high temperatures, so when installing heating systems, you should use a different type of polymer pipeline - polypropylene reinforced lines. An exception is the pipeline, during the installation of which molecularly cross-linked polyethylene is used. When compared with the ordinary one, it is not afraid of the high temperature that circulates inside and has the following advantages:

• no corrosion;
• small cost;
• long service life;
• light weight;
• low roughness factor;
• different diameters;
• no need for staining or insulation.

Outer and inner diameters

The diameter of polyethylene pipes is one of the important characteristics that should be considered when choosing such products. This value can be specified in several ways. Depending on the measurement method, the diameter may be:

• nominal;
• conditional;
• domestic;
• external;
• outer.

Nominal is the most commonly used. It displays the diameter of the circle in contact with the fitting nipples. The nominal diameter can be external or internal. The conditional diameter of polyethylene pipes is prescribed in the state standard. This value is the nominal value rounded up to 0.1 mm.

The outer or outer diameter is a circle that is formed by the plane of the outer surface. The internal diameter of polyethylene pipes is measured along the circumference of the inner surface.

On sale today you can find pipes that are able to withstand different atmospheric pressure during operation. Among the most common are: SDR 17; SDR 13, 6 and SDR 11. The first pipe has a pressure of 10, the second has 12.5, and the third has 16 atmospheres. These products have different outer and inner diameters, as well as wall thickness.

The outer diameter of the lower pressure pipe varies from 25mm to 630mm. The inner diameter can be equal to the limit from 21.2 to 547.4 mm. The wall thickness in this case is equal to a figure from 2 to 37.4 mm. One linear meter of such a pipe weighs 69.9 kg maximum. The minimum value is 0.152kg.

Additionally about diameters

The diameters of the polyethylene pipe will be different if you have a product marked SDR 13, 6 in front of you. In this case, the outer diameter remains the same, but the inner diameter will vary from 21.2 to 527.8 mm. The wall thickness is 2.1 mm minimum and 46.3 mm maximum. Weighs one linear meter of pipe 0.154 - 84.8 kg.

Before buying, you should be aware of the diameters of the SDR 11 polyethylene pipe, which can withstand 16 atmospheres. The outer diameter remains the same, but the inner diameter changes from 20.4 to 503.8 mm. The wall thickness is equal to the limit from 2.3 to 57.2 mm.

When choosing a pipe, you should be careful, because Russian manufacturers indicate external diameters, while foreign manufacturers indicate internal ones. More in demand today are large-diameter polyethylene pipes. Their main areas of use are:

• pressure pipelines;
• storm sewer drainage systems;
• sewers.

Pros of big pipes

PE pipes, whose outer diameter is quite large, have an advantage, among them should be highlighted:

• low cost;
• a small mass;
• environmentally friendly;
• sealing strength;
• impact and stretch resistance.

If suddenly water freezes in such pipes, it will not hurtmaterial. The length also depends on the diameter. For example, products larger than 160 mm in diameter can be purchased in lengths from 3 to 12 m. If you need products with a smaller diameter, they can be of any length, sold in coils or coils.

Pipe assignment for 110 mm

The polyethylene pipe with a diameter of 110 mm is made of low-pressure material by extrusion. Products are easy to install and low cost, and they can be used in many areas. The main area of application is the protection of low-voltage and power electrical wires from damage during hidden laying.

You can buy such a pipe by paying 149 rubles. per running metre. If we compare this product with plumbing, the first one is non-pressure, which means that it can be used for storm sewers or cable laying. It is sold in sections of 12 and 13 m. If desired, you can make an order for sections of any length that will be convenient for installation and delivery.

What else to look out for

The pipe is not able to withstand rupture pressure, so it cannot be laid using the HDD method. The product is produced in several versions, each of which differs in wall thickness. This parameter can vary from 4.2 to 10 mm. Butt welding is most often used to connect pipe segments. Although not recommended, a socket connection may be used. Compression fittings are great too. You can usespecial fittings for connecting elements.

Welding features

What diameters polyethylene pipes have, you now know. However, for the installation of these products, it is necessary to familiarize yourself with the features of docking. Connections may or may not be detachable. The former provide for the possibility of disassembling the system during operation. To create such a connection, steel flanges are used. During operation, disassembly cannot be carried out if the connection is permanent.

The last kind can be implemented in one of two ways. The first involves the use of butt welding technology, while the second method is the welding of pipes with couplings. Welding of large-diameter polyethylene pipes is carried out using thermoresistive fittings and the method of butt-welding pipes. The connection is monolithic in both cases and very reliable.

Features of butt welding and installation

Butt welding requires the use of welding equipment. Simplification of the installation process leads to the absence of the need for additional parts. This technology is relevant only for HDPE pipes of the same diameter. Butt welding can be of high quality only if it is performed with one seam. This ensures equal contact strength of the parts.

Butt mount technology is the most efficient and versatile. When using thisThe technique preserves the flexibility of the material along the length of the pipeline. This process is not difficult, regardless of the type of pipeline installation, which can be traditional, open or trenchless.

If you decide to butt weld, you should use a heating tool. To do this, the ends of the elements to be welded are installed in the center of the welding unit. After alignment and secure fixing, the ends of the pipes must be cleaned of dirt and dust with a napkin. The surfaces to be welded are processed by a mechanical facing device. As soon as you get a uniform chip, the thickness of which is not more than 0.5 mm, you must stop the manipulation, remove the device and check the mutual parallelism with your hand. If there is a gap between the surfaces to be welded, which is greater than the allowable value, the trimming manipulations must be repeated.

Use a non-stick heating tool to heat the ends of the pipes. When the fusion reaches the highest phase, the surfaces must be parted and the heating element removed from the welding zone. The surfaces to be welded are then joined. After that, the clamping pressure must be increased evenly until the value reaches the required value. The seam should be kept under a certain pressure for a while.