This specification covers seven grades of diesel fuel oils suitable for various types of diesel engines. These grades are: Grade No. 1-D S15; Grade No. 1-D S500; Grade No. 1-D S5000; Grade No. 2-D S15; Grade No. 2-D S500; Grade No. 2-D S5000; and Grade No. 4-D. The requirements specified for diesel fuel oils shall be determined in accordance with the following test methods: flash point; cloud point; water and sediment; carbon residue; ash; distillation; viscosity; sulfur; copper corrosion; cetane number; cetane index; aromaticity; lubricity; and conductivity.