system of constructional sewage pipes and fittings, urban sewage water supply and pipes , telecommunication pipes
One of the reasons for the success of PVC pipes in the market is their old dating. PVC was discovered in 1913 and the first polymer tubes produced in 1934 were made of PVC. But in addition to 80 years old, despite the arrival of new rivals, the good performance of PVC pipes during this period has kept these pipes in place. Experiments conducted on PVC pipes over 50 years of age show that their performance is still in line with current standards. Today statistical analyses have shown that the life span of PVC pipes can be considered to be about 100 years or more. Now PVC Pipes have replaced other pipes due to the price and the proper function for all the needs of the industry, such as water and sewage. The highlights of PVC pipes include: corrosion resistance, chemical resistance, high strength and light weight, easy installation, Long-term tensile strength, resistance to wear and abrasion, low friction coefficient, water quality preservation, low thermal and electrical conductivity, flame resistance, production from PVC resin with low-value sources and help preserve national resources, cost-effective and recycling capabilities. Table 1 presents the most important properties of the most common polymeric pipes.

         Table 1: Properties of the most common polymeric Pipes
                                                                       
 
As you can see, the first major factor affecting the quality of the pipeline system, the component properties, the long-term tensile strength and the elasticity modulus of the PVC, is very significant compared to the other polymer materials used in making the pipe and fittings. The properties that determine the main operational parameters of designing pipes used in the water and wastewater industry, namely the ability of the pipe to bear the hydrostatic pressure and the ring stiffness. The high tensile strength and the modulus of elasticity of PVC make it necessary to achieve a certain amount of nominal pressure or ring stiffness, the smaller the thickness of the pipe, this makes it an important advantage, including an increase in the area of the cross-sectional area of the flow in the pipe and its lower weight.
 
The second factor affecting the quality of the pipelines is the pipe connection technology. The need for polyethylene pipes for plastic welding to ensure pipeline sealing may be considered as a more efficient method than the primer or adhesive used in PVC pipes, but apart from the possibility of failure in the fusion joints due to the expansion and contraction caused by temperature changes, the use of heavy and expensive welding tools, especially for large size of pipe, makes work difficult and sensitive. Therefore, PVC pipes have important advantages over their plastic competitors due to their ease of connection and high sealing safety.
 
In addition, PVC pipes have a minimum roughness coefficient due to their high internal wall thickness compared with all types of plastic pipes. According to authoritative scientific references, roughness coefficients for PVC pipes are usually 0/010 and for other plastic pipes 0/122 in hydraulic analysis studies. Therefore, in such circumstances, it can be acknowledged that (taking into account the equal conditions for other parameters effective in hydraulic design and analysis to select the diameter of the lines), the PVC pipes have the potential to flow more fluid flow compared to other pipes in the same interior diameters. In addition, these types of pipes have less fouling capability in the inner wall of the pipe, which is another advantage in terms of the ability of fluid flow through the pipe.