Question 456Steam Plants - Assistant Engineer

The correct answer is C) Seconds Furol. The viscosity of residual fuel oils is measured in Saybolt Seconds Furol (SSF). This is a standardized test method specified by the American Society for Testing and Materials (ASTM) for determining the viscosity of heavier fuels, including residual fuel oils. The Saybolt Seconds Furol scale is used to quantify the time it takes for a fixed volume of the fuel to flow through a standard orifice, which is directly related to the fuel's viscosity. The other options are incorrect because Saybolt Milliliters Universal and Saybolt Millimeters Universal are not standard units for measuring the viscosity of residual fuel oils, and Saybolt Minutes Universal is not a recognized viscosity measurement scale.