many thanks
the question now is why FG remains B31.3 ( normal fluid service ) while it's Slip stream from LNG Process Gas which is NFPA59a. consequence of failure of FG or Process gas for same pipe size would be the same, if both come from the same feed gas.
NFPA 59A requires 30%RT butt welds ( above -29C) as per 9.7.3.2 (B) Pressure piping operating above ?20°F (?29°C) shall have 30 percent of each day’s circumferentially welded pipe joints nondestructively tested over the entire circumference, in accordance with ASME B 31.3.
1- is Fuel Gas...