ASTM D1298 for density of crude petroleum and liquid petroleum products
ASTM D1298 for density of crude petroleum and liquid petroleum products by hydrometer method
7. Sampling
7.1 Unless otherwise specified, samples of non-volatile petroleum and petroleum products shall be taken by the procedures described in Practices D 4057 (API MPMS Chapter 8.1) and D 4177 (API MPMS Chapter 8.2).
7.2 Samples of volatile crude petroleum or petroleum products are preferably taken by Practice D 4177 (API MPMS Chapter 8.2), using a variable volume (floating piston) sample receiver to minimize any loss of light components which may affect the accuracy of the density measurement. In the absence of this facility, extreme care shall be taken to minimize these losses, including the transfer of the sample to a chilled container immediately after sampling.
7.3 Sample Mixing - may be necessary to obtain a test portion representative of the bulk sample to be tested, but precautions shall be taken to maintain the integrity of the sample during this operation. Mixing of volatile crude petroleum or petroleum products containing water or sediments, or both, or the heating of waxy volatile crude petroleum or petroleum products may result in the loss of light components. The following sections (7.3.1 to 7.3.4) will give some guidance on sample integrity maintenance.
7.3.1 Volatile Crude Petroleum and Petroleum Products Having an RVP Greater than 50 kPa - Mix the sample in its original closed container in order to minimize the loss of light components.
NOTE 1 - Mixing volatile samples in open containers will lead to loss of light components and consequently affect the value of the density obtained.
7.3.2 Waxy Crude Petroleum - If the petroleum has a pour point above 10°C, or a cloud point or WAT above 15°C, warm the sample to 9°C above the pour point, or 3°C above the cloud point or WAT, prior to mixing. Whenever possible, mix the sample in its original closed container in order to minimize the loss of light components.
7.3.3 Waxy Distillate - Warm the sample to 3°C above its cloud point or WAT prior to mixing.
7.3.4 Residual Fuel Oils - Heat the sample to the test temperature prior to mixing (see 8.1.1 and Note 4).
7.4 Additional information on the mixing and handling of liquid samples will be found in Practice D 5854 (API MPMS Chapter 8.3).
