4.1 The estimate of oxidation stability is useful in controlling the continuity of this property for batch acceptance of production lots having the same operation. It is not intended that this test method be a substitute for Test Method D943 or be used to compare the service lives of new oils of different compositions.

4.2 This test method is also used to assess the remaining oxidation test life of in-service oils.

1.1 This test method2 utilizes an oxygen-pressured vessel to evaluate the oxidation stability of new and in-service turbine oils having the same composition (base stock and additives) in the presence of water and a copper catalyst coil at 150°C.

1.2 Appendix X1 describes a new optional turbine oil (unused) sample nitrogen purge pretreatment procedure for determining the percent residual ratio of RPVOT value for the pretreated sample divided by RPVOT value of the new (untreated) oil, sometimes referred to as a “% RPVOT Retention.” This nitrogen purge pretreatment approach was designed to detect volatile antioxidant inhibitors that are not desirable for use in high temperature gas turbines.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3.1 Exception—Other units are provided in parentheses (psi, grams, and inches), because they are either the industry accepted standard or the apparatus is built according the figures in this standard, or both.

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. For specific warning statements, see 6.2, 6.4, 6.5, 6.6, and 6.10.