ASTM D5950 Test Method for Pour Point of Petroleum Products (Automatic Tilt Method)
11. Procedure
11.1 Pour the sample into the test specimen jar to the scribed mark. When necessary, heat the sample in a water bath or oven until it is just sufficiently fluid to pour the sample into the test specimen jar. Samples with an expected pour point above 36°C or samples which appear solid at room temperature can be heated above 45°C, but should not be heated above 70°C (see Note 4).
11.2 Subject the test specimen to the following preliminary treatment or use the instrument's automatic preheat option.
NOTE 6 - Residual fuels have been known to be sensitive to thermal history. In the case where a residual fuel sample is tested, refer to Test Method D97 for sample treatment.
11.2.1 When the expected pour point (EP) is known to be ≤-33°C, heat the test specimen to 45°C in a bath or oven maintained at 48°C.
11.2.2 When the expected pour point (EP) is known to be >-33°C, heat the test specimen to EP + 9°C, or at least to 45°C but no higher than 70°C (see Note 4).
11.3 Place a cork disk at the bottom of the jacket in the required cell and fit a cork ring to the test jar. The cork ring should be 25 +/- 3 mm above the bottom of the test jar.
11.4 Place the test jar in the selected test cell. Attach the detector head according to the manufacturer's instructions.
11.5 Select the desired testing interval (1 or 3°C).
11.6 Enter the expected pour point (EP). If 3°C testing intervals are chosen (11.5) you must enter an expected pour point that is a multiple of 3°C.
11.7 Start the test in accordance with the manufacturer's instructions.
11.8 At this point, the instrument shall monitor the test specimen with the optical detector, adjusting the jacket temperature to the first temperature level (according to Table 1) and measuring the specimen temperature. The instrument shall automatically change the jacket temperature in accordance with the specimen temperature (according to Table 1). The time to move the jacket temperature from one level to the next lower level shall not exceed 90 s. The instrument shall start tilting the specimen (without removing it from the jacket) in the prescribed manner when the temperature of the test specimen is at 9°C higher than the expected pour point. If the specimen flows during the tilting movement, the no-flow point is not reached and the jacket returns to the waiting vertical position for the next test. The test will continue until the jacket is in a complete horizontal position and the detector does not detect any movement of the specimen for 5 s. This temperature, the no-flow point, plus 1 or 3°C (depending on the test interval selected) is the pour point of the oil (see Fig. 1). When the pour point is determined, the instrument shall display the pour point result and start to reheat the test specimen.
11.9 If the instrument detects the no-flow point on the first tilting cycle (EP + 9°C), disregard the result and start with 11.1 using a higher expected pour point.
11.10 Record the result as the pour point without any correction.
NOTE 7 - Residual fuels have been known to be sensitive to thermal history. In the case where a residual fuel sample is tested, refer to Test Method D97 for sample treatment.
