PEX (or cross-linked polyethylene) is a part of the water supply piping system. Compared with the metal pipe (copper, iron, lead) or hard plastic pipe (PVC, CPVC, ABS) system, it has many advantages. It is flexible, resistant to scale and chlorine, will not corrode or produce pinholes, can be installed faster than metal or hard plastic, and has fewer connections and accessories.
PEX pipe is made of cross-linked HDPE (High Density Polyethylene) polymer. HDPE is melted and continuously extruded into a PEX . The crosslinking of HDPE is accomplished by one of three different methods.
PEX pipelines have been used in Europe since around 1970, and were introduced to the United States around 1980. Since then, the use of PEX has been increasing, replacing copper pipes in many applications, especially radiant heating systems installed on floors or flat panels under walkways. Recently in the United States, there has been an increase in interest in PEX for hot and cold water pipelines.
