As of NFGC (NFPA 54) 2018:
-
“arc-resistant” (conductive black jacket) CSST only requires a bonding to an effective ground-fault path and is considered bonded if connected to an appliance that is grounded via its EGC (unless local codes say otherwise)
-
an above ground in or attached to a building gas system with any yellow jacket (none arc-resistant, none conductive) CSST requires “additional” bonding, even when connected to a grounded appliance, for “lightning protection”, usually accomplished with a clamp and a bonding jumper (no longer than 75 ft, #6+) connected directly to the grounding electrode.