参考文献，1。ISO 11922、1，1997，Thermoplastics，pipes。for the、conveyance.of，fluids，Dimensions,and。tolerances,Part.1,Metric,series，2.ISO，TR 10839，2000 Polyethylene、pipes、and、fittings。for the supply,of.gaseous。fuels Code，of，practice。for，design.handling.and installation,3,IEC.60529。2001.Degrees。of。protection。provided by enclosures，IP，code。4,EN，12117，1997、Plastics、piping、systems、Fittings valves,and、ancillaries，Determination、of,gaseous。flow、rate、pressure。drop.relationships，5 IS0、12176，1、1998 Plastics.pipes,and.fittings.Equipment for fusion jointing、polyethylene。systems Part、1,Butt fusion，6、IS0 12l76 2 2000,Plastics。pipes,and.fittings，Equipment for，fusion.jointing.polyethylene，systems,Part.2.Electrofusion、7.EN.1555。3.2002,Plastics,pipimg,systems,for the、supply.of。gaseous.fuels.Polyethylene、PE Part、3，Fittings