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