Which operation may cause the pressure in an...

🔍 Key Concepts

• Inert gas systems on tankers and how they maintain safe pressure and oxygen levels in cargo tanks • What happens to tank pressure when cargo or vapors are removed versus when they are added or heated • The difference between operations that consume or draw out vapors and those that introduce gas or create expansion

💭 Think About

• For each option, ask yourself: does this operation tend to REMOVE cargo/vapor from the tank, or ADD/EXPAND it? How would that affect pressure? • Which operation requires particular attention to keeping the inert gas system running so the tank does not go below the minimum pressure? • Think about which operation could create a slight vacuum in the tank if the inert gas flow or pressure is not carefully controlled.

✅ Before You Answer

• Identify which operation would most likely reduce the volume of gas/vapor inside the tank. • Confirm which operations generally heat or add vapors, tending to increase or maintain pressure rather than lower it. • Before choosing, match the operation to a situation where tank vacuum or under-pressure is a known risk that must be avoided.

Which operation may cause the pressure in an inert tank to fall below the prescribed limits?

Discharging

Crude oil washing

Steaming tanks