Degradation of hydraulic fluids and turbine oils, because of oxidation or thermal breakdown, can result in the formation of acids or insoluble solids and render the oil unfit for further use.

This test method can be used to estimate the relative oxidation stability of petroleum-base oils. It should be recognized that correlation between results of this test and the oxidation stability in use can vary markedly with service conditions and with various oils.

1.1 This test method covers a procedure for evaluating the oxidation stability of petroleum base hydraulic oils and oils for steam and gas turbines.

1.2 This test method was developed to evaluate the oxidation stability of petroleum base hydraulic oils and oils for steam and gas turbines.

1.2.1 Rust and oxidation inhibited hydraulic, anti-wear hydraulic and turbine oils of ISO 32–68 viscosity were used to develop the precision statement. This test method has been used to evaluate the oxidation stability of fluids made with synthetic basestock and in-service oils; however, these fluids have not been used in cooperative testing to develop precision data.

1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.4 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. Identified hazardous chemicals are listed in 7.3, 7.6, and 7.8. Before using this test method, refer to suppliers' safety labels, Material Safety Data Sheets, and other technical literature.