when repairing or replacing new fuel line,
is there any precaution to cut the old line?.
which standard shall I refer to?
General speaking: what preparation shall be done to cut fuel line?
actually, I went through All ASME concerning piping but I did not find any statement or specific procedure and precaution on how to replace old hydrocarbon piping.
regards
To replace the existing process piping, it may need to involve all the parties, such as the engineering, operation, as well as maintenance. The new piping needs to be complied with eh Code and Standard, and the replacement work needs to follow the procedures as specified by O&M in terms of the safety.
Be careful even if you got a hot permit to cut/weld a fuel gas line. I had seen a terrible incident where the welder went on flames even after operation tested the line gas free.
Positive isolation is a must and all pockets such as valve (between seats) must be vented/drained. Bottom line, don’t take any chance with fuel lines. Check with operation the possibility of internal build-up and it’s flammability.