Fittings for metal-plastic pipes have the same function as fittings for metal pipes. To connect them to the pipes, a collet is used. They can also be transitional from a collet to a threaded joint, for joining metal-plastic pipes and metal pipes. One of the most reliable connections for metal-plastic pipes is a press connection (press-fitting compound). It is achieved by crimping the metal-plastic pipe around the fitting of the fitting with a stainless steel sleeve. Each press fittings manufacturer has its own crimping profile. As a tool for crimping, either a tool recommended by the manufacturer of press fittings (which is correct) or a third-party press tool with a press clamp of a certain internal profile corresponding to this fitting is used. Next on popularity after press fittings are known fittings with a split ring or compression fittings, which are designed for connecting metal-plastic pipes of heating and water supply systems by open wiring. The connecting elements of diameters 16, 20, 26, 32 mm are used in operation. This system is serviceable, which cannot be used for hidden wiring.
As for sanitary fittings for polypropylene pipes, welding is used to connect to the pipes. Welding is usually performed by a special device that heats the bonded surfaces up to 260 ° C. Fittings are also transitional from a welded joint to a threaded joint for connecting polypropylene pipes and metal pipes.