🔍 Key Concepts

• LNG (Liquefied Natural Gas) cargo tank level alarms and their normal sequence (High vs HI-HI) • Difference between normal process controls and emergency shutdown systems (ESD) • Purpose of an automatic overflow protection at very high liquid levels

💭 Think About

• When a tank reaches HI-HI level, is the system responding to a routine operating condition or a potentially dangerous overfill situation? • Which type of shutdown is specifically intended to prevent cargo from physically overflowing the tank and spilling? • Think about which system should act first: a local/process control or a safety-critical automatic trip designed for overfill protection?

✅ Before You Answer

• Verify which device is linked specifically to maximum safe liquid level (overfill) protection, not just normal control • Check if HI-HI level is typically tied to a dedicated overfill/overflow protection system on LNG carriers and terminals • Confirm that the chosen option would stop further loading into the tank automatically when the HI-HI point is reached