ASTM D5800 method for evaporation loss of lubricating oils by the Noack method
4. Summary of Test Method
4.1 A measured quantity of sample is placed in an evaporation crucible or reaction flask that is then heated to 250°C with a constant flow of air drawn through it for 60 min. The loss in mass of the oil is determined.
4.2 Interlaboratory tests have shown that Procedure A, Procedure B, and Procedure C yield essentially equivalent results, with a correlation coefficient of R(2) = 0.996. See the research report for the Selby-Noack interlaboratory study.
5. Significance and Use
5.1 The evaporation loss is of particular importance in engine lubrication. Where high temperatures occur, portions of an oil can evaporate.
5.2 Evaporation may contribute to oil consumption in an engine and can lead to a change in the properties of an oil.
5.3 Many engine manufacturers specify a maximum allowable evaporation loss.
5.4 Some engine manufacturers, when specifying a maximum allowable evaporation loss, quote this test method along with the specifications.
5.5 Procedure C, using the Selby-Noack apparatus, also permits collection of the volatile oil vapors for determination of their physical and chemical properties. Elemental analysis of the collected volatiles may be helpful in identifying components such as phosphorous, which has been linked to premature degradation of the emission system catalyst.
