WATER SEPARABILITY OF PETROLEUM OILS: ASTM D1401
(Equivalent Test Methods: IP 412, ISO 6614, and AFNOR T60-125)
EXPLANATION
This test method measures the ability of petroleum oils or synthetic fluids to separate from water. It is used for specification of new oils and monitoring of in-service oils.

TEST SUMMARY
A 40-mL sample and 40 mL of water are stirred for 5 min at 54° C in a graduated cylinder. The time required for the separation of the emulsion thus formed is recorded. If complete separation or emulsion reduction to 3 mL or less does not occur after standing for 30 min, the volumes of oil (or fluid), water, and emulsion remaining at the time are reported.

TEST PRECISION
See figure below for precision.