🔍 Key Concepts

• Crude oil washing (COW) safety precautions and how static electricity can build up in lines and machines • The purpose of clearing or not clearing oil in COW lines after washing is complete • How shipboard procedures usually deal with lines containing flammable cargo: gravity drain vs. compressed air vs. leaving lines full

💭 Think About

• Which option best minimizes the risk of static discharge or over‑pressure in the COW piping system? • Think about which methods (gravity, compressed air, pump suction, or leaving the line full) are normally allowed or restricted by COW manuals and industry codes for cargo lines carrying crude oil. • If you leave oil in the line between operations, what could happen to that oil (temperature change, expansion, leakage), and is that considered safe?

✅ Before You Answer

• Check which choices might create high velocity flow or excessive turbulence in a line containing crude oil vapors. • Consider whether using compressed air in a crude oil line is normally permitted by regulations or company procedures. • Verify which method allows the line to be cleared in a controlled, low‑energy, low‑pressure way, directing the oil to a safe cargo tank.