ASTM D2880-23

1.1.1 Grades No. 0-GT S5000, No. 0-GT S500, and No. 0-GT S15 includes naphtha, Jet B, and other light hydrocarbon liquids that characteristically have low flash point and low viscosity as compared with kerosine and fuel oils.

1.1.2 Grades No. 1-GT S5000, No. 1-GT S500, and No. 1-GT S15 are a light distillate fuel oil suitable for use in nearly all gas turbines.

1.1.3 Grades No. 2-GT S5000, No. 2-GT S500, and No. 2-GT S15, which is a heavier distillate than Grade No. 1-GT, can be used by gas turbines not requiring the clean burning characteristics of Grade No. 1-GT. Fuel heating equipment may be required by the gas turbine depending on the fuel system design or ambient temperature conditions, or both.

1.1.4 Grade No. 3-GT may be a heavier distillate than Grade No. 2-GT, a residual fuel oil that meets the low ash requirements, or a blend of distillate with a residual fuel oil. Fuel heating will be required by the gas turbine in almost every installation.

1.1.5 Grade No. 4-GT includes most residuals and some topped crudes. Because of the wide variation and lack of control of properties, the gas turbine manufacturer should be consulted with regard to acceptable limits on properties.

1.2.1 Appendix X1 describes the five grades of gas turbine fuels covered by this specification. Further, it states the significance of various test methods used in inspecting the fuels.

1.2.2 Appendix X2 discusses the sources of fuel contaminants and notes the significance of such contaminants in the operation of gas turbines and gas turbine fuel systems. The particular significance of trace metals in gas turbine fuels is noted. Upper limits of trace metals are recommended for the various grades of gas turbine fuels, but these recommended limits do not constitute a requirement of the specification unless mutually agreed upon by the interested parties. Limitations due to the use of used or recycled oil are also noted.