ASTM D5985 Test Method for Pour Point of Petroleum Products (Rotational Method)
11. Procedure
11.1 Transfer the specimen into the test specimen cup to the scribed mark. When necessary, heat the sample in a water bath or oven until it is just sufficiently fluid to transfer into the test specimen cup. Samples with an expected pour point above 36°C or which appear solid at room temperature can be heated above 45°C but shall not be heated above 70°C (see Note 4).
11.2 Samples of residual fuels, black oils, and cylinder stock, which have been heated to a temperature higher than 45°C during the preceding 24 h or when the thermal history of these sample types is not known, shall be kept at room temperature for 24 h before testing.
11.3 Make sure that the cooling well is free of moisture. If it is not, remove all moisture by wiping with a dry cloth. Insert the test specimen cup into the cooling well. Bring the measuring head into position over the test specimen cup and lower it into the test specimen.
11.4 Start the test program following the manufacturer's instructions.
11.5 When the expected pour point is known to be higher than -33°C, preselect a starting temperature which is at least 9°C higher than the expected pour point, but at least 45°C. The highest starting temperature that can be programmed is 70°C.
11.6 When the expected pour point is known to be at or below -33°C, the test duration can be shortened by preselecting a starting temperature which is at least 9°C higher than the expected pour point. The lowest starting temperature that can be programmed is 20°C.
11.7 When the expected pour point is not known and the sample appears to be liquid, preselect a starting temperature of 45°C. The apparatus automatically heats the test specimen to approximately 45°C when a starting temperature is not selected. When the expected pour point is not known and the sample needs to be heated before transferring into the test specimen cup, preselect a starting temperature of 70°C.
11.8 Initially, the test specimen is heated to approximately 45°C, or to the starting temperature preselected by the operator between 20 and 70°C. The test specimen cup is continuously rotated at approximately 0.1 rpm and flow of the cooling fluid from the circulating bath is regulated to maintain the cooling block at a temperature approximately 8°C lower than the test specimen temperature. The test specimen temperature is continuously displayed. At the detection of the last flow point, the temperature the test specimen attained is held on the digital display until reset by the operator. The test specimen is then heated to approximately 45°C, or to the preselected temperature.
11.9 The test specimen temperature rounded up to the next 3°C integer is also displayed.
