ASTM D6751 Standard Specification for Biodiesel Fuel Blend Stock (B100)
ASTM D6751 Standard Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels
5. Test Methods
5.1 The requirements enumerated in this specification shall be determined in accordance with the following methods.
5.1.1 Flash Point - Test Methods D93, except where other methods are prescribed by law. Test Methods D3828 or D6450 can also be used. The precision and bias of Test Methods D3828 and D6450 with biodiesel is not known and is currently under investigation. Test Methods D93 shall be the referee method.

5.1.2 Water and Sediment - Test Method D2709. Test Method D1796 may also be used. Test Method D2709 shall be the referee method. The precision and bias of these test methods with biodiesel is not known and is currently under investigation.

5.1.3 Viscosity - Test Method D445.

5.1.4 Sulfated Ash - Test Method D874.

5.1.5 Sulfur - Test Method D5453. Other test methods may also be suitable for determining up to 0.05 % sulfur in biodiesel fuels such as Test Methods D1266, D2622, D3120 and D4294 but may provide falsely high results (see X1.5) although their precision and bias with biodiesel is unknown. Test Method D5453 shall be the referee test method.

5.1.6 Corrosion - Test Method D130, 3 h test at 50°C.

5.1.7 Cetane Number - Test Method D613.

5.1.8 Cloud Point - Test Method D2500. Test Method D3117 may also be used because the two are closely related. Test Method D2500 shall be the referee test method. The precision and bias of these test methods for biodiesel is not known and is currently under investigation.

5.1.9 Acid Number - Test Method D664. Test Methods D3242 or D974 may also be used. Test Method D664 shall be the referee test method.

5.1.10 Carbon Residue - Test Method D4530. A 100 % sample shall replace the 10 % residual, with percent residue in the original sample reported using the 10 % residual calculation (see X1.9.1). Test Methods D189 or D524 may also be used. Test Method D4530 shall be the referee method.

5.1.11 Total Glycerin - Test Method D6584.

5.1.12 Free Glycerin - Test Method D6584.

5.1.13 Phosphorus Content - Test Method D4951.

5.1.14 Distillation Temperature, Reduced Pressure - Test Method D1160.

6. Workmanship
6.1 The biodiesel fuel shall be visually free of undissolved water, sediment, and suspended matter.

7. Keywords
7.1 alternative fuel; biodiesel fuel; diesel fuel oil; fuel oil; renewable resource