ASTM D525 Test Method for Oxidation Stability of Gasoline (Induction Period Method)
1. Scope
1.1 This test method covers the determination of the stability of gasoline in finished form only, under accelerated oxidation conditions.
NOTE 1 - Caution: This test method is not intended for determining the stability of gasoline components, particularly those with a high percentage of low boiling unsaturated compounds, as these may cause explosive conditions within the apparatus. However, because of the unknown nature of certain samples, the pressure vessel assembly shall include a safety burst-disc in order to safeguard the operator.
NOTE 2 - For measurement of oxidation stability of gasoline by measurement of potential gum, refer to Test Method D873, or IP Test Method 138.
NOTE 3 - The precision data were developed with gasolines derived from hydrocarbon sources only without oxygenates.
1.2 The accepted SI unit of pressure is the kilo Pascal (kPa); and for temperature in °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:
D873 Test Method for Oxidation Stability of Aviation Fuels (Potential Residue Method)
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
E 1 Specification for ASTM Thermometers
2.2 IP Standards:
IP-138 Test Method for Oxidation Stability, Aviation Gasoline
Part IV - Petroleum and its Products
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 break point - the point in the pressure-time curve that is preceded by a pressure drop of exactly 14 kPa within 15 min and succeeded by a drop of not less than 14 kPa in 15 min.
3.1.2 induction period - the time elapsed between the placing of the pressure vessel in the bath and the break point at 100°C.
