What is the fuel oil expansion factor used in exams?

• A. .0003
• B. .0005
• C. .0002
• D. .001

Answer: (B)

Thermal expansion of fuel oil is what this question tests. In bunkering and tank-topping calculations, a standard expansion factor is used to account for how much the fuel’s volume changes with temperature. For fuel oil, the commonly accepted expansion factor is 0.0005 per degree Celsius, meaning the volume increases by 0.05% for every °C rise in temperature.

For example, if you have 1000 m³ of fuel at the reference temperature and the fuel temperature rises by 10°C, the expansion would be 1000 × 0.0005 × 10 = 5 m³. So the volume becomes about 1005 m³. This helps ensure you don’t under- or overfill tanks and bunkers due to temperature-related volume changes.

Other values would overstate or understate the expansion for typical fuel oils, which is why 0.0005 per °C is the standard choice used in exams.