Which term describes the capacity of a fuel to resist degradation over time?

• A. Storage Stability
• B. API Gravity
• C. Flashpoint
• D. Auto-Ignition Temperature

Answer: (A)

Storage stability is the capacity of a fuel to resist degradation over time, especially while it sits in storage, so its quality and performance properties don’t deteriorate. Over time fuels can degrade due to oxidation, moisture, heat, or impurities, which can cause gum formation, sediment, increased acidity, and changes in viscosity or volatility. Keeping storage stability high helps ensure the fuel will still meet specifications when it’s used, and it guides how long the fuel can be stored and what conditions are required (such as temperature control or stabilizers).

The other terms describe different characteristics: API gravity is about how dense the fuel is relative to water, not how it holds up over time; flashpoint is the temperature at which vapors ignite and is a safety/ignition measure, not a measure of storage durability; auto-ignition temperature is the temperature at which the fuel will ignite without a spark, also a combustion-related property rather than storage stability.