Exam Question

### (a) The need to monitor temperature of fuel in service tanks
Monitoring the temperature of fuel oil, particularly heavy fuel oil (HFO), in service tanks is critical for safety, operational efficiency, and regulatory compliance.
* **Viscosity Control for Combustion:** The primary reason for heating HFO is to reduce its viscosity to the required level for correct atomization by fuel injectors (typically 12-18 cSt at the engine inlet). The temperature in the service tank (e.g., 85-95°C) is the first stage of this process, ensuring the fuel can be effectively pumped and further heated by viscosity regulators before injection. Incorrect viscosity leads to poor atomization, incomplete combustion, increased fuel consumption, carbon deposits, and thermal loading on engine components.
* **Fire and Explosion Prevention (SOLAS):** Fuel oil must be stored and handled at a temperature safely below its flash point. SOLAS Chapter II-2, Regulation 4 mandates that the temperature of heated oil must be kept at least 10°C below its flash point (which is a minimum of 60°C for marine fuels). Overheating can generate flammable vapors, creating an explosive atmosphere within the tank ullage space and posing a severe fire risk in the engine room.