This specification covers grades of fuel oil intended for use in various types of fuel-oil-burning equipment under various climatic and operating conditions. These grades include the following: Grades No. 1 S5000, No. 1 S500, No. 2 S5000, and No. 2 S500 for use in domestic and small industrial burners; Grades No. 1 S5000 and No. 1 S500 adapted to vaporizing type burners or where storage conditions require low pour point fuel; Grades No. 4 (Light) and No. 4 (Heavy) for use in commercial/industrial burners; and Grades No. 5 (Light), No. 5 (Heavy), and No. 6 for use in industrial burners. Preheating is usually required for handling and proper atomization. The grades of fuel oil shall be homogeneous hydrocarbon oils, free from inorganic acid, and free from excessive amounts of solid or fibrous foreign matter. Grades containing residual components shall remain uniform in normal storage and not separate by gravity into light and heavy oil components outside the viscosity limits for the grade. The grades of fuel oil shall conform to the limiting requirements prescribed for: (1) flash point, (2) water and sediment, (3) physical distillation or simulated distillation, (4) kinematic viscosity, (5) Ramsbottom carbon residue, (6) ash, (7) sulfur, (8) copper strip corrosion, (9) density, and (10) pour point. The test methods for determining conformance to the specified properties are given.

1.1 This specification (see Note 1) covers grades of fuel oil intended for use in various types of fuel-oil-burning equipment under various climatic and operating conditions. These grades are described as follows:

1.1.1 Grades No. 1 S5000, No. 1 S500, No. 2 S5000, and No. 2 S500 are middle distillate fuels for use in domestic and small industrial burners. Grades No. 1 S5000 and No. 1 S500 are particularly adapted to vaporizing type burners or where storage conditions require low pour point fuel.

1.1.2 Grades No. 4 (Light) and No. 4 are heavy distillate fuels or middle distillate/residual fuel blends used in commercial/industrial burners equipped for this viscosity range.

1.1.3 Grades No. 5 (Light), No. 5 (Heavy), and No. 6 are residual fuels of increasing viscosity and boiling range, used in industrial burners. Preheating is usually required for handling and proper atomization.

1.2 This specification is for the use of purchasing agencies in formulating specifications to be included in contracts for purchases of fuel oils and for the guidance of consumers of fuel oils in the selection of the grades most suitable for their needs.

1.3 Nothing in this specification shall preclude observance of federal, state, or local regulations which can be more restrictive.

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.