🔍 Key Concepts

• Fuel oil impurities vs. fuel properties (solids, water, sludge vs. flash point or calorific value) • How impurities are typically measured or separated before analysis (e.g., sediment/water separation) • Difference between lab test equipment and shipboard handling methods

💭 Think About

• Ask yourself: which option clearly allows you to separate or quantify the non-fuel material (sediment, water, sludge) in the sample? • Which choices are mainly used to measure energy content or flash point/safety characteristics, rather than impurity percentage? • Think about normal engine-room practice: how do we actually determine how much dirt or water is in the oil, not just improve fuel quality?

✅ Before You Answer

• Identify which method is specifically associated with measuring sediment/water content in fuel, not just storing or burning it. • Eliminate any option that mainly measures heat value (calorific value) or ignition/flash characteristics, since those do not directly give impurity percentage. • Confirm that the remaining method is a laboratory procedure, not just a shipboard operational step.