ASTM D1401
WATER SEPARABILITY OF PETROLEUM OILS AND SYNTHETIC FLUIDS.
This test method covers measurement of the ability of petroleum oils or synthetic fluids to separate from water. Although developed specifically for steam-turbine oils having viscosities of 28.8?mm2/s to 90?mm2/s at 40?°C, this test method may be used to test oils of other types having various viscosities and synthetic fluids at other test temperatures. It is recommended, however, that the test temperature be raised to 82?°C ± 1?°C when testing products more viscous than 90?mm2/s at 40?°C.