PPR pipes are produced in the group of machines called extruder line. Fittings are produced in injection machines using moulds for shaping. It is a highly safe product and has a high cost while it also has electro fusion types. Since this level of high quality is not generally required, it is preferred rarely. The products with the wall-thickness that are called PN20 by the standards are produced at PN25 by our company. The reason for this is that the environmental resistance value of the raw material is ? = 8 MPa. Under normal conditions wall-thickness should be decreased for PN20. However, tables included in the standards havent been revised for this raw material class, pressure group has been increased in order not to be out of standards.