While routine, closed-loop transfers are inherently safe from internal static ignition, bonding and grounding become critical whenever the system is opened to the atmosphere or when specific maintenance activities generate massive static charges. When we break the closed loop or introduce external energy, the hazard profile shifts from NFPA 58 back to the static mitigation principles found in NFPA 77, Recommended Practice on Static Electricity or API RP 2003, Protection Against Ignitions Arising Out of Static, Lightning, and Stray Currents. Here are the specific scenarios where bonding and grounding are required: