49 C.F.R. § 193.2517 Purging.
Title 49 - Transportation
When necessary for safety, components that could accumulate significant amounts of combustible mixtures must be purged in accordance with a procedure which meets the provisions of the AGA “Purging Principles and Practice” after being taken out of service and before being returned to service.
Title 49: Transportation
PART 193—LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS
Subpart F—Operations
§ 193.2517 Purging.