HDPE pipe: self-assembly, installation features and instructions

Polyethylene pipes are universal due to the excellent material characteristics. Increasing use in everyday life is found in the HDPE pipe. Installation can be done by oneself, if everything is done according to the rules. This does not require a special qualification.

Material specifications

The high demand for HDPE pipes is due to the high quality of the material:

• Temperature range - from -50 ⁰ С to +60 ⁰ С;
• Resistance to acidic and alkaline environments;
• High elasticity and strength;
• Low thermal conductivity;
• Polyethylene is not a conductor of electric current.

Application of pipes

In the house or at the cottage of HDPE pipes are manufactured:

• Drainage and drainage;
• water pipes;
• Gas supply to the house;
• Cable duct for wiring.

Pipe Selection

For pipes with drinking water, pipes with a diameter of no more than 60 mm with a wall thickness of 4 mm are purchased. They must be designed for working pressure of the liquid in the system not lower than 1 MPa. Advantage is the absence of corrosion and taste of metal near the water. If it is required to equip hot water supply, it is necessary to know that at 80 ⁰ С the polyethylene softens, and when it rises it starts to melt. In this regard, you should choose a brand not lower than PE80. For hot water pipes can also be marked PE-PT or PN20, they withstand heating to 110 ⁰ C. For domestic conditions this is quite enough.

It is necessary to distinguish pipes for water supply and non-pressure pipes. For ordinary operating conditions of the water supply, bays of 25 m in length with a wall thickness of at least 2 mm are taken. If the main pipeline is operated under good pressure and has a diameter of more than 25 mm, then an inch pipe is taken as the withdrawal. In any case, the branch must be smaller than the total water supply.

Ways to connect HDPE pipes

Before installation, choose the connection method, which can be as follows:

1. Non-detachable - electrofusion or butt welding. The connection is of the same strength as the pipe itself.
2. Connector method - socket, compression and flange connection. Such pipeline systems are easy to assemble and dismantle, it is possible to repair or install in hard-to-reach places. Connections are made using fittings.

The method of connection is chosen depending on the following factors:

• Pipe diameters;
• Type of operation: non-pressure, pressure, cabling;
• The use of reinforcement from different materials and with different diameters;
• Site availability;
• Availability of welding equipment.

The most durable are welded and flanged joints. The threaded coupling with sealing is unstable to loads. Installation of HDPE pipes for water pipes with compression fittings is usually done on personal plots for irrigation systems of plants.

The weakest joints are the bell joints. They are used only in non-pressure pipes, except when the connection is made welded.

Compression fittings for HDPE pipes: installation

For HDPE pipes, mainly plastic fittings are used, but there are also stronger options from steel, cast iron, copper and brass. They differ in design and can be welded, threaded, with a press connection. For plastic pipes, the compression fittings are predominantly used, where the fixing is performed by a clamping ring made of hard plastic with notches, and sealing by tightening the O-rings.

Like other connecting devices, compression fittings come in several forms:

• Clutch - for connecting pipes of equal diameter and direction;
• Transition - for fastening pipe ends whose diameters are different (metal-polyethylene transition possible);
• Branch, angle - make the turn of the structure to 45-120 ⁰ ;
• A tee, a cross - to create branches;
• Choke - a device for connecting the pipe with a hose;
• Plug - for sealing the ends of pipes.

Before laying a water pipe, you first need to draw a diagram of it with all the fittings and valves. The unfolded pipe tends to twist, so it is fastened with clamps or pressed in a straightened state for 2 days.

If a HDPE pipe is selected for installation, installation is often done with compression fittings.

1. The pipe is cut to the desired size with a special tool. You can use an ordinary hacksaw for metal, but the end while doing this is flat and cleared of burrs.
2. The hole is leveled by the calibrator, since its oval shape is inadmissible. An external chamfer is made on the end face.
3. The body of the fitting is neatly connected to the pipe, so as not to damage the rubber seals. Planting will be easier if the water is moistened with a joint.
4. Hand tighten the union nut. You can apply a key to ensure the necessary connection density.
5. For the second pipe, the procedure is repeated.

Connections with compression fittings are useful when installing HDPE pipes at the dacha. The system is easy to assemble in the spring on a site and in the autumn to dismantle.

Split connections in hard-to-reach places are not made. It is convenient to use electric couplings with a built-in heater. The fitting connects two pipes, after which its heating is turned on and welding takes place with the formation of an integral unit. The price of the device is high, but the method is effective and is often used.

Despite the possibility of dismantling in compression fittings, rubber seals should be replaced when reinstalled. This will ensure high reliability of the structure.

Flange connections

When the HDPE pipe is installed, it is preferable to mount the mounting for a diameter of more than 40 mm using metal flanges. For this, the pipe edges are cut with a pipe cutter at a right angle to the finished marking. Then polyethylene sleeves with beads are welded to them, and metal flanges are mounted on them. Another method is to mount a compression flange on the pipe to fix a smooth polymer joint. Then a standard flange is mounted, which is fastened with studs and bolts with a similar piece installed at the end of the steel pipe.

Flanged connection allows connecting valves, regulators, latches and pipes to each other.

Welded joints

Just like metal products, a HDPE pipe can be welded. Installation by own hands is made with the help of special equipment with electric heating of the junction points.

1. The joints are cleaned and welding equipment is being prepared.
2. The welding parameters are set.
3. Pipes are fixed in the clamps of the welding machine and centered. The ends are machined mechanically.
4. Between the pipes are installed heaters, with which the edges are melted.
5. The ends are reduced under pressure, which is maintained until cooling.
6. Pipes are extracted from the clamps.

The cost of installing HDPE pipes by welding depends on the diameter, but up to 63 mm the price is usually the same and is about 200 rubles. Over the joint.

When using an electric clutch, the installation costs are the same as for butt welding, but it has a higher price. As a result, the cost is more.

Hydraulic testing

The working capacity of the collected water pipe is checked by filling with water for 2 hours. The system is then pressurized and maintained for 30 minutes. The pipeline is inspected for leaks.

During operation, the state of the system is constantly monitored. If properly assembled, it will function for a long time.

Errors in the installation of HDPE pipes

1. It is important to take into account the linear expansion of the pipes from the effect of temperature. If you forget about it, the voltage inside the pipes exceeds the norm, which shortens the period of their operation.
2. Too much distance between the attachments causes the pipeline to sag, which leads to its premature failure.
3. Pipes are cemented only with insulation.
4. To prevent condensation on the surface, the hot or cold water supply pipes are isolated.
5. During installation, the fitting is disassembled so that the pipes come in as far as they will go. If you do not fully untighten the nut, then push the pipe into the connector with force, it may not penetrate deeply enough. When the installation of HDPE pipes is done by oneself at the dacha for the irrigation system, leaks are not so dangerous, but this is unacceptable for domestic water supply. Regardless of the consequences in both cases, you must create a tight connection.
6. Excessive tightening of the adapters leads to their destruction or slipping of the gaskets from the installation sites.

Conclusion

When the HDPE pipe is installed, the installation is done mainly by welding or compression fittings. If you follow the installation rules, the connections will be sealed and durable for many years.