ASTM D892 Foaming Characteristics of Lubricating Oils
This method measures the tendency of an oil to foam by aerating a fixed volume of oil at a fixed flow rate of air through a gas diffuser submerged in oil. The volume of foam after 5 minutes aeration and the volume of foam after 10 minutes settling are recorded. Sequence I, II and III are performed at 24°C (75°F), 93.5°C (200°F) and 24°C (75°F) respectively.
After the foam collapses from Sequence II, the same aliquot is tested in Sequence III. This is done to address concerns associated with agitation, dispersion of anti-foaming agents, and possible presence of volatiles which can effect results. Sequence IV is a special procedure for Mercon Transmission Fluid with increased flow rate and temperature.
Note: Foam is not entrained air.