FED-STD-791D
6.2.7.3 Determine whether a correction is required in the reading of recorded
temperature. Estimate the correct time to make the first pour stability determination at the
correct thermometer temperature ("1C).
6.2.8 Pour stability determinations are made at the temperatures specified for the SAE
grades of the test samples. The determination whether a test sample is "fluid" or "solid" at the
specified temperature is conducted as follows:
6.2.8.1 Select the SAE grade test sample to be checked.
6.2.8.2 Carefully remove the test jar vertically from the bath and slowly tilt 90 to
horizontal position. For 5 s observe the surface of the sample for movement.
NOTE 2: Handle jars at stopper end only to prevent heating the sample. If frosting
occurs, wipe jars with cloth or glove; do not use unprotected finger.
6.2.8.3 If the surface moves, the sample is "fluid". If no movement is detected, the
sample is "solid".
6.2.8.4 Select the duplicate test sample and repeat pour stability determination (see
6.2.8.2 and 6.2.8.3).
6.2.8.5 If additional SAE grades are included in the test bath, repeat all steps in 6.2.8 for
the remaining duplicate test samples at specified temperatures.
6.2.9 Alternate method for determination of stable pour point. In this determination, the
viscosity grade of the oil is not relevant. The stable pour point is determined during the final
cool down in the temperature/time cycle as follows:
6.2.9.1 At the sample temperature of -5C, carefully remove the test jar vertically from
the bath and carefully tilt only enough to ascertain whether the oil surface moves and is "fluid".
If movement is detected while tilting, return the bottle to vertical and carefully replace in bath.
Total time for this operation shall be less than 3 s.
NOTE 3: Handle jar at stopper end only to prevent heating the sample. If frosting
occurs, wipe jar with a cloth or glove; do not use unprotected finger.
6.2.9.2 If no movement of the oil is detected when the jar is tilted to 90 (horizontal) for
5 s the sample is "solid".
6.2.9.3 For oils which remain fluid, repeat step 6.2.9.1 at successively lower
temperatures, in 3C increments, until no movement of the oil is detected and the oil is "solid" by
6.2.9.2. Record the reading of the temperature measurement sample thermometer.
24
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business