Is used to refer only to the heaviest commercial fuel that can be obtained from crude oil, heavier than gasoline and naphtha.
1. Heavy Fuel Oil 180 CST (Centistoke):
2. Heavy Fuel Oil 380 CST (Centistoke):
Overall Classification: Heavy Fuel Oil (HFO) is categorized based on its viscosity, with 180 CST and 380 CST representing different levels of thickness and density. These grades of HFO are primarily used in applications that require a dense and energy-rich fuel source, such as marine engines and industrial power generation.