ASTM D3242 Acidity in Aviation Turbine Fuel
Low levels of acidity in aviation turbine fuels, such as that remaining from refining, may damage the metals in turbine systems. This test determines low levels of acidity (from 0.000 to 0.100 mg KOH per gram of sample) in aviation turbine fuels.
The sample is placed in an Erlenmeyer flask, titration solvent and indicator are added, and nitrogen is bubbled through the solution. The mixture is titrated with potassium hydroxide to a color-changing endpoint. The blank is corrected for and the acid number is reported in mg KOH per gram or sample.