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