🔍 Key Concepts

• Diesel fuel properties when stored for long periods in partially filled tanks • How temperature changes affect air space in a fuel tank (condensation, moisture) • Why critical equipment like emergency generators need reliable, clean fuel supply

💭 Think About

• Think about what happens inside the empty space above the fuel in a tank when the ambient temperature goes up and down. • Which of the listed problems would be most affected by how full the tank is, rather than by fuel quality or filtration? • For an emergency generator that may sit idle for long periods, what type of contamination risk increases when there is more air space in the tank?

✅ Before You Answer

• Focus on the role of air space vs. liquid volume in a closed tank. • Ask yourself which option is directly related to water or humidity getting into the fuel. • Eliminate any choices that would mainly be controlled by filters, strainers, or pump design, not tank level.