🔍 Key Concepts

• Pressure/vacuum (P/V) valves purpose on cargo tanks • Relationship between P/V valves and P/V breakers in the venting system • Standard maintenance and inspection expectations for safety devices

💭 Think About

• Think about what normally causes small pressure changes in a closed cargo tank and how the system handles them. • Consider which device should act first in normal operation: the P/V valve or the P/V breaker? Why would that order be safer? • Ask yourself whether safety‑critical valves on cargo tanks are typically left alone or kept in reliable condition by routine care.

✅ Before You Answer

• Verify which component is intended to handle routine, small volume breathing of the tank atmosphere. • Confirm that the set points for P/V valves are arranged so they act before any backup or emergency devices. • Remember that industry practice and regulations generally require regular inspection and cleaning of critical safety valves—check which options reflect that.