Petroleum product testing — gasoline flash point determination For motor gasoline (flash point typically below 50°C), which laboratory apparatus is specified to determine the flash point in the low range?

Introduction / Context:
Flash point is the lowest temperature at which vapors above a liquid ignite momentarily upon exposure to a test flame. For volatile fuels like gasoline, low-range closed-cup methods are required to capture the early onset of flammable vapor formation safely and reproducibly.

Given Data / Assumptions:

• Product: gasoline (high volatility; very low flash point).
• Methods differ by temperature range and volatility.
• We are concerned with flash points below 50°C.

Concept / Approach:
The Abel closed-cup apparatus is designed for determining low flash points (sub-ambient to around 65°C) and is historically specified for highly volatile products. Pensky–Martens is commonly used for higher flash point fuels like diesel and lubricants, not for gasoline.

Step-by-Step Solution:
Identify volatility of gasoline → very high; requires low-range closed-cup method.Match to apparatus: Abel is a low-temperature, closed-cup method appropriate for flash point < 50°C.Therefore, Abel apparatus is correct.

Verification / Alternative check:
Standards and handbooks align Abel (or Tag closed cup) with low flash liquids; Pensky–Martens targets higher flash products.

Why Other Options Are Wrong:

• Pensky–Martens: better for diesel, furnace oil (higher flash), not gasoline.
• Saybolt chromometer: measures color/viscosity characteristics, not flash point.
• None of these: incorrect since Abel is appropriate.

Common Pitfalls:

• Using open-cup methods or high-range apparatus for gasoline, giving unsafe or misleading results.

Final Answer:
Abel apparatus