Storage safety by flash point – pick the safe fuel Petroleum liquid fuels with flash point greater than 66 °C are generally considered safer in storage/handling. Which listed fuel normally has a flash point above 66 °C?

Introduction / Context:
Flash point is the lowest temperature at which a liquid emits enough vapour to momentarily ignite. Fuels with higher flash points are safer for storage and handling in ambient conditions. Many standards classify liquids by flash point thresholds such as 23 °C, 60/61 °C, and around 66 °C for practical safety guidance.

Given Data / Assumptions:

• The question uses a threshold of 66 °C as a “safe” indicator.
• We compare typical fuels: petrol, naphtha, kerosene, heavy fuel oil.
• Typical property ranges apply; exact numbers vary by grade.

Concept / Approach:
Light products (naphtha, gasoline) have very low flash points (well below room temperature) and are Class I flammable liquids. Kerosene typically has a mid-range flash point (often around 38–72 °C depending on grade), sometimes above 66 °C but not guaranteed for all grades. Heavy fuel oil (residual fuel) has a high flash point, commonly far exceeding 66 °C, because it is composed of heavy, low-volatility components.

Step-by-Step Solution:

Verification / Alternative check:
Material specifications for residual fuels list high flash points, while kerosene specifications allow a lower minimum, making HFO the safer blanket choice.

Why Other Options Are Wrong:

• Kerosene: May be above 66 °C for some grades but not universally; the question asks which fuel has FP > 66 °C in general.
• Naphtha / Petrol: Both have FP below ambient, hence not safe under this criterion.

Common Pitfalls:
Assuming kerosene is always high-flash; verify grade-specific limits.

Final Answer:
Heavy fuel oil