Fuel gas lines in non-hazardous areas must be all-welded without leakage points like flanges or valves.
: Specific requirements for piping connected to rotating equipment (like pumps and compressors) to prevent excessive nozzle loads. norsok l002 pdf
Piping Fabrication, Installation, Flushing, and Testing (latest edition 2016). Fuel gas lines in non-hazardous areas must be