The provisions of Part 4, Chapter 6, Section 4 (referred to as Section 4-6-4) apply to piping systems – other than liquid cargo systems – serving tanks and normally dry spaces. Piping systems for normally dry spaces include gravity drain and bilge systems. Systems for tanks include ballast systems, fuel oil and lubricating oil storage and transfer systems, and vent, overflow and sounding systems. Additional requirements for fuel oil and lubricating oil systems relating to operation of internal combustion engines are provided in Section 4-6-5. Additional requirements for liquid cargo piping, vent and overflow, sounding, bilge and ballast systems for specialized vessels are provided in Part 5.