2710.19.11 - Testing 25 degrees A.P.I. or more

This HTS category, 2710.19.11, encompasses distillate and residual fuel oils, including blended fuel oils, that have a specific gravity of 25 degrees A.P.I. or more. This classification is applied to fuel oils with a density greater than or equal to 0.9032 at 15°C (60°F). These products are typically used as fuels in industrial furnaces, boilers, and some diesel engines, representing a distinct sub-segment of fuel oils based on their density.

It is important to distinguish this category from its sibling, 2710.19.06, which covers fuel oils testing *under* 25 degrees A.P.I. The API gravity scale is inversely related to specific gravity, meaning a higher API gravity indicates a lower specific gravity and a lighter oil, while a lower API gravity suggests a higher specific gravity and a heavier oil. Therefore, the key differentiator is the measured API gravity, with this category specifically addressing the heavier fuel oils within the broader "distillate and residual fuel oils" group.

This classification serves as a heading for further subdivision based on viscosity. The subcategories within 2710.19.11 are defined by their Saybolt Universal viscosity at 37.8°C (100°F). These include "light fuel oils" with a viscosity of less than 45 seconds, "No. 4-type fuel oils" with a viscosity between 45 and 125 seconds, and "heavy fuel oils" with a viscosity exceeding 125 seconds. This further breakdown allows for more precise classification based on the flow characteristics of the fuel oil, which are critical for determining its appropriate use and handling.