What is the maximum mg/L limit for F76 fuel (CFD)?

• A. 1.5
• B. 2.64
• C. 3.0
• D. 2.0

Answer: (B)

Fuel cleanliness is expressed as the amount of solid contaminants per liter of fuel (mg/L). For F76 fuel used in CFD applications, the maximum allowed level is 2.64 mg/L. This limit comes from the CFD fuel cleanliness specification and is set to protect fuel-system components from abrasion and clogging, ensuring reliable operation of pumps, filters, and injectors across naval equipment. The value represents a practical upper bound that balances testing practicality, manufacturing variability, and engine tolerances. A lower limit would be stricter and harder to meet, while a higher limit would increase the risk of deposits and filter plugging in service. To verify compliance, a fuel sample is collected, solids are separated and dried, weighed, and then expressed as mg/L by dividing the mass of solids by the volume of fuel. If the measured solids exceed 2.64 mg/L, the fuel would fail cleanliness testing and require filtration, stabilization, or replacement.