ASTM D873 Oxidation Stability of Aviation Fuels (Potential Residue Method)
1. Scope
1.1 This test method covers the determination of the tendency of aviation reciprocating, turbine, and jet engine fuels to form gum and deposits under accelerated aging conditions.
NOTE 1 - Caution: This test method is not intended for determining the stability of fuel components, particularly those with a high percentage of low boiling unsaturated compounds, as these may cause explosive conditions within the apparatus.
NOTE 2 - For the measurement of the oxidation stability (induction period) of motor gasoline, refer to Test Method D525.
1.2 The accepted SI unit of pressure is the kilo pascal (kPa); the accepted SI unit of temperature is °C.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D381 Test Method for Existent Gum in Fuels by Jet Evaporation
D525 Test Method for Oxidation Stability of Gasoline (Induction Period Method)
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
E 1 Specification for ASTM Thermometers
3. Terminology
3.1 Definitions of Terms Specific to This Standard
3.1.1 The following definitions of terms are all expressed in terms of milligrams per 100 mL of sample, after "X" hours aging, "X" being the accelerated aging (oxidation) period at 100°C.
3.1.1.1 potential gum - sum of the soluble and insoluble gum.
3.1.1.2 precipitate - sediment and suspended material in the aged fuel, obtained by filtering the aged fuel and washings from the glass sample container.
3.1.1.3 insoluble gum - deposit adhering to the glass sample container after removal of the aged fuel, precipitate, and soluble gum. Insoluble gum is obtained by measuring the increase in mass of the glass sample container.
3.1.1.4 soluble gum - deterioration products present at the end of a specific aging period. These deterioration products exist in solution in the aged fuel and as the toluene-acetone soluble portion of the deposit on the glass sample container. The soluble gum is obtained as a nonvolatile residue by evaporating the aged fuel and the toluene-acetone washings from the glass sample container.
3.1.1.5 total potential residue - sum of the potential gum and the precipitate.
