ASTM D975 standard specification for diesel fuel oils
6. Workmanship
6.1 The diesel fuel shall be visually free of undissolved water, sediment, and suspended matter.

7. Requirements
7.1 The grades of diesel fuel oils herein specified shall be hydrocarbon oils, except as provided in 7.3, with the addition of chemicals to enhance performance, if required, conforming to the detailed requirements shown in Table 1.

NOTE 5 - Additives are generally included in finished diesel fuel to improve performance properties (cetane number, lubricity, cold flow, etc.).

7.2 Grades No. 2-D S15, No. 2-D S500 and No. 2-D S5000 - When a cloud point less than -12°C is specified, as can occur during cold months, it is permitted and normal blending practice to combine Grades No. 1 and No. 2 to meet the low temperature requirements. In that case, the minimum flash point shall be 38°C, the minimum viscosity at 40°C shall be 1.7 mm2/s, and the minimum 90 % recovered temperature shall be waived.

7.3 Alternative Fuels and Blend Stocks:
7.3.1 Fuels Blended with Biodiesel - The detailed requirements for fuels blended with biodiesel shall be as follows:
7.3.1.1 Biodiesel for Blending - If biodiesel is a component of any diesel fuel, the biodiesel shall meet the requirements of Specification D6751.

7.3.1.2 Diesel fuel oil containing up to 5 vol% biodiesel shall meet the requirements for the appropriate grade No. 1-D or No. 2-D fuel, as listed in Table 1.

7.3.1.3 Test Method D7371 shall be used for determination of the vol% biodiesel in a biodiesel blend. Test Method EN 14078 may also be used. In cases of dispute, Test Method D7371 shall be the referee test method. See Practice E29 for guidance on significant digits.

7.3.1.4 Diesel fuels containing more than 5 vol% biodiesel component are not included in this specification.

7.3.1.5 Biodiesel blends with No. 4-D fuel are not covered by this specification.

8. Precautionary Notes on Conductivity
8.1 Accumulation of static charge occurs when a hydrocarbon liquid flows with respect to another surface. The electrical conductivity requirement of 25 pS/m minimum at temperature of delivery shall apply when the transfer conditions in Table 2 exist for the delivery into a mobile transport container (for example, tanker trucks, railcars, and barges).

9. Keywords
9.1 biodiesel; biodiesel blend; diesel; fuel oil; petroleum and petroleum products