Fall 1998
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New Selby-Noack Volatility Test offers precision and safety

Hazards associated with the Wood's Metal heating approach of the conventional Noack apparatus have been overcome in recently developed Selby-Noack Volatility equipment from Tannas shown below. The new automated benchtop unit has been designed for safe, precise running of ASTM D 5800 Standard Test Method for Evaporation Loss of Lubricating Oils by the Noack Method.

The Noack test has been in wide use in Europe for many years and more recently in North America and Japan since becoming an ILSAC GF-2 specification in 1996. The test measures the evaporation loss, or volatility, of an engine oil by heating an oil sample at 250°C for 60 minutes while drawing air across its surface. The percentage of the sample volatilized is reported as the test result.

To improve the safety and precision of the Noack method, R&D Director Ted Selby began researching an alternative instrumental approach in 1993 using a noble-metal heater directly fused to the glass sample container. This provides uniform heating without the toxic fumes of Wood's Metal, a mixture of lead, bismuth, antimony and cadmium.

In addition, Selby developed a unique "coalescing valve" for the apparatus which controls collection of nearly 100 percent of the volatilized oil. Elemental analysis can then be used to determine the composition of these volatiles. This can be important in identifying and quantifying components of the volatiles such as phosphorous which has been linked to premature degradation of the emission system catalyst.

With completion of research in 1997 Tannas began production of the units for precision testing in interested laboratories. An interlaboratory study involving Pennzoil, PetroCanada, Sun Oil, Savant and Tannas was completed in June 1998. Nine oils used in previous round robins were tested in duplicate by each lab. Results showed good precision and correlation with Wood's Metal Noack equipment.

Further data on the precision and correlation of the two approaches to measuring Noack volatility will be generated in a new round robin to be conducted in October by the ASTM Oil Volatility Surveillance Panel of Section B0.07 on Bench Tests. Also during October the Selby-Noack procedure will be balloted in Subcommittee D02.06 on Analysis of Lubricants for inclusion as Procedure B in ASTM D 5800.