As the polyethylene pipes with high density can not withstand high temperatures,it can not solve the problem of indoor water supply.Therefore,the United States has developed a newtype of high temperature pipe of polyethylene (PE-RT)with heat-resistance property.In addition to all the advantages of the High-density polyethylene,Italso provide a good solution to the indoor water supply.Heat-resistant polyethulence is a copolymer with ethylence-octence as the copolymers monomer.In the polymerization reaction,the number and distribution of the polyethylene branched chain ha been under an appropriate conttol,making the PE-RT material have excellent mechanical properties.Without crosslinking,PE-RT pipe would have a high temperature resistance.At a water supply temperatureof 70,its service life can last as long as 50 years even under a pressure of 0.97Mpa for a long-term use.