Installation of polyethylene pipes in the ground.
Structural material HDPE( low pressure polyethylene) is one of the derivatives in the polymerization of ethylene and has a high plasticity and is not affected by corrosive media. These properties, as well as frost resistance, made the HDPE material indispensable in the production of plumbing products, and in particular, pipes for water and gas communications. Products made of low-density polyethylene can be conditionally divided into three components: 
- communications for supplying water and heat to living quarters;
- pipes for gas pipeline installation;
- sewer pipes for drainage and drainage of water.
Also from this material it is possible to make and completing armature, for installation of the above systems.
The qualitative characteristics of polyethylene allow it to be used both in domestic communications and on large industrial scales, when it is necessary to lay large-sized HDPE pipes in the ground, withstanding high pressures of water or gas. The diameter and length of the pipes depend only on the operating conditions and the needs of the customers.
All work on the installation and installation of pipes must begin with calculations. It's great if you have a site plan already with the developed scheme of communication laying. If not all the buildings exist in reality, do not forget to bring them into the project, so that in the future there will be no problem. Water supply and sewerage should always be taken into account during construction. At the first stage, it is necessary to make trenching, since HDPE pipes are installed underground. Depending on the purpose of the system( water supply or sewerage), the method of connecting the polyethylene pipes is chosen: 
- mechanical fastening of joints, using fittings;
- welded joint.
The easiest way is a detachable joint of pipe joints. With this method of assembly, HDPE pipes are connected by means of seals and fittings. With a competent selection of docking parts, the communication can be laid either directly or rotated to the right or left, as depicted in your diagram. Laying HDPE pipes under the ground with their own hands is quite an affordable operation, which does not require the use of additional tools and tools. This method is very simple and effective, but there is a drawback - the possible flow of the system. 
Sewer system of polyethylene pipes connected by welded fittings is a more complicated process, since it is necessary to use a special welding machine. If you can not afford it, and you will not use it often, the best way is to rent an electric welding machine for a short time. The main and most important thing is to clean the joints of the pipes. Even a small amount of dirt will become a catalyst for poor quality of the welded joint. It is most convenient for the pipe to weld the joint into a joint. For this, it is necessary to heat the ends of the welded structures( pipes) and compress them. More details on the process of welding HDPE pipes, see the video.
The fineness of the installation of HDPE pipes by welding.
Most likely, with the first independent experience, a seam is likely to be visible, an ideal joint of pipe joints will come with work experience. It should not be discouraged and significantly worried for the pioneers of this type of work, there are special mechanisms and devices for cleaning the joints of pipes, which give a 100% result. 
The laying of HDPE pipes in the ground will provide the user with a long service life, in which there will be no problems after the application of dry cleaning agents. With proper handling, this water pipe is suitable for all sewer systems.
