49 C.F.R. § 195.104 Variations in pressure.
Title 49 - Transportation
If, within a pipeline system, two or more components are to be connected at a place where one will operate at a higher pressure than another, the system must be designed so that any component operating at the lower pressure will not be overstressed.
Title 49: Transportation
PART 195—TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE
Subpart C—Design Requirements
§ 195.104 Variations in pressure.