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