🔍 Key Concepts

• 46 CFR Part 153 requirements for inert gas systems on tank vessels • The purpose of minimum positive pressure in an inerted tank (to prevent air ingress and ignition risk) • Typical order of magnitude of low positive pressures used for tank inerting (well below atmospheric pressure values like 14.7 psig)

💭 Think About

• Think about why an inert gas system needs only a small overpressure instead of very high pressure—what is the system really trying to prevent? • Compare each choice with what would be practical and safe for large cargo tanks and their structure. • Which value looks more like a typical tank blanket/inerting pressure rather than a storage cylinder or high‑pressure system?

✅ Before You Answer

• Verify in 46 CFR Part 153 the specific section that states the minimum inert gas system pressure requirement (look for a number in psig). • Check that the value you choose is a small but clearly positive pressure above atmospheric, not a high‑pressure value. • Confirm that the pressure is reasonable for continuous operation on a cargo tank without overstressing tank boundaries.