🔍 Key Concepts

• Crude Oil Washing (COW) system layout and purpose • Differences between blanks and valves as means of isolation • SOLAS / tanker safety philosophy on positive physical separation between fire main and cargo systems

💭 Think About

• Ask yourself: if crude oil could backflow into the fire main, what type of isolation would provide the most reliable, visible separation? • Which options are mechanical devices that stop flow in one direction versus those that physically separate the piping? • On a tanker, when doing maintenance, which device lets you positively prove there is no connection between two systems?

✅ Before You Answer

• Identify which choices are true valves and which are solid physical barriers. • Consider tanker design: what does SOLAS/industry practice favor when preventing cross-contamination between fire main and cargo system? • Verify which device can fail internally versus which gives a guaranteed, visible break in the line.