ASTM D5772 Standard Test Method for Cloud Point of Petroleum Products and Liquid Fuels (Linear Cooling Rate Method)
8. Sampling
8.1 Obtain a sample in accordance with Practice D4057 or D4177.
8.2 Samples of very viscous materials may be warmed until they are reasonably fluid before they are sampled. However, no sample should be heated more than absolutely necessary.
8.3 The sample shall not be heated above 70 °C. When the sample is heated above 70 °C, allow the sample to cool below 70 °C before filtering or inserting into the apparatus.
8.4 When moisture is present in the sample, remove the moisture by a method such as filtration through dry, lint-free filter paper until the oil is perfectly clear. Make such filtration at a temperature at least 14 °C above the expected cloud point.
NOTE 1 - Moisture will be noticed in the sample as a separate phase or as a haze throughout the entire sample. Generally, a slight haze will not interfere with the detection of the wax cloud.
9. Preparation of Apparatus
9.1 Prepare the instrument for operation in accordance with the manufacturer's instructions.
9.2 Clean and dry the test cell using suitable solvents as prescribed by the manufacturer.
9.3 Prepare the refrigerated circulating bath for operation in accordance with the manufacturer's instructions and allow it to attain a temperature at least 20 °C lower than the expected cloud point of the sample.
10. Calibration and Standardization
10.1 Ensure that all of the manufacturer's instructions for calibrating, checking, and operating the apparatus are followed.
10.2 A sample with a mutually agreed upon cloud point can be used to verify performance of the apparatus.
