6.2　Piping Layout for Hydrogen Service

6.2.1　The piping for hydrogen service should be routed above ground.

6.2.2　The piping for hydrogen service shall be weld joined；however，flanged joint may be used when the piping is connected to equipment or valves.

6.2.3　The piping for wet hydrogen service shall have a slope not less than 0.003，and drain shall be provided at low point of the piping.

6.2.4　Flame arrestor in hydrogen vent piping shall be located close to vent end.